CLA Connect Open Forum

3 phase vs 1 phase

  • 1.  3 phase vs 1 phase

    Posted 04-10-2018 09:58
    Edited by Erwin B 04-10-2018 09:58
    Good morning. Not sure if anyone has tackled this but i'm trying to see with the new inverter drives on the machines today if there would still be considerable savings in electricity wiring equipment 3 phase? Or how much better is it compared to single phase?  The cost to wire is pretty high wiring 100 machines hehe. I just want to make sure its worth it. Has anyone come across this issue? Thanks for any input you may have. i have the Latest 2018 huebsch.

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    Erwin B
    Store Owner/ Employee
    Los Angeles CA
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  • 2.  RE: 3 phase vs 1 phase

    Posted 04-10-2018 10:08
    ​If your wired for three phase use it, if you have to add wiring to get three phase to each washer, in my opinion the savings is not worth the cost. These new inverter drives save about 10% off your electric bill over standard single phase machine with capacitors.

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    Mike B
    Multi Store Owner
    Sunny Palm Harbor Florida
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  • 3.  RE: 3 phase vs 1 phase

    Posted 04-10-2018 13:28
    Erwin, check the specs on both that have the same output power etc.  I am pretty sure that once an inverter is used the same wattage will occur.  The inverter duty motor that is matched with single phase  .... will be 3 phase anyway with no capacitors needed.  This is based on my experience when we came up with our 902-1092 G-force extractors using the shells of older models.

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    Michael Walsh www.kingkoin.com
    Store Owner/ Employee
    King Koin Laundry, Car n Dog Wash
    Bismarck ND
    ------------------------------



  • 4.  RE: 3 phase vs 1 phase

    Posted 04-10-2018 23:47
    The label on the machine will answer this for you.
    Max wattage or amps at each voltage/phase is what you are looking for.
    If you only have a single phase service on the building now it don't matter much.
    Also which ever you choose BE SURE your Electrician balances your phases.

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    Joe M
    Store Owner/ Employee
    Nassau NY
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  • 5.  RE: 3 phase vs 1 phase

    Posted 04-11-2018 01:38
    There are machines out there that do not do well on three phase with their inverters. If you want to have that brand then do not upgrade (not yet) to three phase. Will not expand. But it works like this. The power company delivers power to you that you can choose to use one leg to ground or two legs using no neutral reference. Or three legs again using no neutral reference. They are delivering to you a current divided into three. How you choose to use that current depends on what your bill will be. If you use just one leg of that delivered current you will pay what your current draw will be. If you choose to divide that by half by using two then that is what your current draw will be. Should you decide to divide your machine across three different wires your bill will one third of what using that same machine on one leg would be. Well not exactly but very close.
    That is the answer to your actual question.
    Now as far as inverters they just use less billable power. Period. How much less depends on how many of those three wires you choose to give them power to run your equipment.
    If you want to get into sine wave that will have to be for another day.

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    Curt Harrington

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  • 6.  RE: 3 phase vs 1 phase

    Posted 04-11-2018 12:23
    Ditto on what Joe said ... the balancing of the 3 phase needs to be done by an electrician who really knows his trade.  Regardless of the number of wires used mainly means ... that it will be the same total amps-wattage but with more wires with more phases the gauge of wires needed will be less per wire.  We are talking non capacitor inverter grade motors for either the 1 phase or the 3 phase.  To be fair to Curt ... there could be an exception ... I am going by how impressed I was when I did some clamp on ammeter readings for total amperage flow on my Hitachi off the shelf vfd-inverters.  They are 1 phase vfd-inverters.

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    Michael Walsh www.kingkoin.com
    Store Owner/ Employee
    King Koin Laundry, Car n Dog Wash
    Bismarck ND
    ------------------------------



  • 7.  RE: 3 phase vs 1 phase

    Posted 27 days ago
    A couple of notes to the foregoing conversation.  When using a clamp on ammeter on the secondary or output side of a VFD make sure it reads in true RMS current. A VFD output consists of 3 outputs of very short positive-going and negative-going pulses that approximate a sine wave. A true RMS ammeter will calculate and display the actual current in the wire.  RMS stands for root mean square which is the name of the formula.

    Power is the product of voltage and current; that is, P=E*I, in the most simple DC circuits.  In AC circuits, other factors are present making them more complicated.  A really good reference for electrical is a book called Ugly's Electrical References, about $14 at Home Depot and well worth keeping handy in a desk drawer.

    I would not use 1 phase 120 V power to supply a VFD, even for fractional HP motors, because of harmonic issues on the neutral or white wire.  Harmonics is a real problem, is difficult to solve, and in extreme cases can cause conductor or terminal failures due to heating.  Rather, use 2 line conductors, 208 V or 240 V to supply the VFD, or, for new installations, use all 3 line conductors.  Yes, you can use a 240 V hi-leg system to feed a VFD, any 2 conductors or all 3 conductors.

    To balance a system where you are using 2 line conductors (of a 3 phase system) to supply each 3 phase VFD, the first washer would get phases A-B; the second washer would get phases B-C; the third washer would get phases C-A.  Repeat that pattern for the next 3 washers. Ditto for dryers if they have VFD's.

    In simple terms, a 3 phase system has 3 conductors each of which is 120 electrical degrees out of phase with the other phases. So, B phase follows A phase by 120 degrees, C phase follows B phase by 120 degrees, and A phase follows C phase by 120 degrees for a total of 360 degrees which is a complete circle or complete revolution of the generator.
    Jim Allen
    Chief Burro

    ------------------------------
    Jim Allen
    Potential Investor
    VIP Laundry
    Orange CA

    Potential InvestorVIP LaundryVIP LaundryJimAllenVIP LaundryVIP Laundry
    ------------------------------



  • 8.  RE: 3 phase vs 1 phase

    Posted 27 days ago
    Jim,

    Thanks for the info.  I do have a digital true RMS clamp on (Fluke 325) & I also have an older clamp on possibly non RMS Amprobe (dial style).  I will have to compare which way it favors too many amps or too few .. as if that would help me use a possible non RMS ... not sure ... I suppose it could just be unreliable & inconsistent with vfds but usable for other amperage draw checks?

    On the neutral use of the 110VAC ... what about laundromat owners who have a portion of their existing electrical is twenty six 110VAC hookups for washers on a continuous bulkhead.  Should they go through the expense of having all of those 26 hookups changed to 220VAC by a qualified person???  It seems like some serious new conduiting & wires adding would be needed back to a sub panel & possibly even to the main panel.

    ------------------------------
    Michael Walsh www.kingkoin.com
    Store Owner/ Employee
    King Koin Laundry, Car n Dog Wash
    Bismarck ND
    ------------------------------



  • 9.  RE: 3 phase vs 1 phase

    Posted 27 days ago
    Edited by Curt Harrington 27 days ago
    I would like to add one thing to what Jim said. There is some equipment out there that while it is 208/240 has a 120V control circuit. If you have a high leg it can not be connected to that line. You can still use the AB BC CA connection pattern just make sure that on the machine the stinger leg is not connected to the control line.
    And if you use all 3 conductors there are some "inverters" that must have the high leg connected to L3.

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    Curt Harrington

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  • 10.  RE: 3 phase vs 1 phase

    Posted 27 days ago
    Curt, i thought the transformer in the machine takes care of that. It should step it down no mater where the stinger is hooked.

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    Chris Mirisciotta
    Store Owner/ Employee
    Canon Coin Laundry
    Canonsburg PA
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  • 11.  RE: 3 phase vs 1 phase

    Posted 27 days ago
    Edited by Michael Walsh 27 days ago
    Chris & others,

    You just gave me a "flashback memory" of when my trusty electrician put in our brand new & newly 3 phase car wash equipment back in 1987 ...  he wisely routed the "wild leg stinger" away from any transformer in line with the control portion of the equipment.  How do I know ... I remember him laughing at my "DIY amateur hour" attempts to put in an add on transformer & destroying (smoke too!)  the brand new transformer.  I did everything else right though ... in my defense.

    Could this be a case of "it is not what he, she or they tell you ... sometimes it is what he, she or they don't tell you"?  I think he was getting even with me about when I told the electrical contractor's office person ... who was the electrician's sister .... "not to believe a single word he was saying ... mostly just kidding of course".  That was when he was on speaker phone with his sister & proclaiming that Mike was planning to save money doing as much electrical work as possible "in house".

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    Michael Walsh www.kingkoin.com
    Store Owner/ Employee
    King Koin Laundry, Car n Dog Wash
    Bismarck ND
    ------------------------------



  • 12.  RE: 3 phase vs 1 phase

    Posted 27 days ago
    Edited by Curt Harrington 27 days ago
    Chris
    I have addressed this issue with the big boys only to be brushed aside. You would think that would be the case but it is not.
    When you install equipment you must be sure (if you have a high leg) to connect it to the proper terminal block on some equipment.

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    Curt Harrington

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  • 13.  RE: 3 phase vs 1 phase

    Posted 27 days ago
    Curt is correct, some equipment requires the hi leg, sometimes called the red leg, to be connected to a certain terminal on the equipment.  That is one reason I don't like hi-leg delta transformers. Whatever is stated in the equipment manual rules.  That is, the ruling document is that page in the manual showing incoming or feed connections.  Some equipment uses the incoming line terminals for reference as well as power.

    Briefly, a VFD, or PWM drive, rectifies to DC voltage all of the incoming line power then stores it on a capacitor bank. The output section takes the DC power and chops it into series of very short duration positive-going and negative-going pulses on 3 different output terminals at a rate of, typically, 4k Hz to 12k Hz. The variable frequency output then runs the motor.

    Michael, I do not know what the TL's do to mitigate harmonics with incoming 120 V if they have a VFD.  There are a number of ways to keep harmonics off the neutral.  One way is to add a line reactor in the TL between the VFD and the plug power.  A line reactor is basically 1/2 of a transformer.  Another way would be some type of filter.  Likely a lot of machinery doesn't even have any input conditioning and they ignore the issue.  Which means that if you put in a number of TL's with VFD's running the motors then you start having problems like neutral wires getting hot or neutral bus bars in feed panels getting hot then you probably have a harmonics problem.  On the other hand, a TL might run for 25-30 minutes then sit idle for a couple of hours during which time everything cools off.  My TL's are pretty old, they use across-the-line starting.

    Jim Allen
    Chief Burro




    ------------------------------
    Jim Allen
    Potential Investor
    VIP Laundry
    Orange CA

    Potential InvestorVIP LaundryVIP LaundryJimAllenVIP LaundryVIP Laundry
    ------------------------------



  • 14.  RE: 3 phase vs 1 phase

    Posted 26 days ago
    Jim,

    I was not referring to top loaders with VFDs.  I could be wrong but it seems like some operators might have installed some double load front loaders (20-25# etc/)with VFDs that use 120 VAC because of the way their bulkhead wiring was previously done.

    If that is the case, based on what you said they may have some other precautions within the equipment from the manufacturer.  Or it might be they are just being lucky that the neutral in not creating problems for the VFD because of cool off times or whatever.  I only have three VFDs & they do not use neutral but are single phase 240VAC not three phase power in that part of my facility.

    There have been times where operators on the forum have lamented about VFD problems ... I wonder if it can be traced back to your more intricate analysis of the use of 120VAC with VFDs.

    ------------------------------
    Michael Walsh www.kingkoin.com
    Store Owner/ Employee
    King Koin Laundry, Car n Dog Wash
    Bismarck ND
    ------------------------------



  • 15.  RE: 3 phase vs 1 phase

    Posted 23 days ago
    In the early days of VFD's, the mid to late 80's, they were subject to all kinds of interference and needed a fair amount of protection.  There are 2 kinds of interference basically, EMI and RFI.  Electromagnetic interference comes in on the power lines while radio frequency interference comes in through the air.  Recognizing which problem you have is the first step.

    But VFD's, previously called PWM drives, also put noise onto the power lines.  Some have built in suppression, some are 'naked' on the line, large drives come with several options depending on where it gets installed, and large parallel drives for parallel motors usually require special consideration or design.  Regardless, the same rules that apply to general electrical motor control work apply to VFD's also.  Keep circuits separate, don't run power circuits parallel to signal or control circuits, all terminals should be tight or torqued (and double checked before power up), tie wrap together noisy power conductors going from the VFD to the motor to take advantage of field cancellation, so on.  One more thing, hard grounding.  Any equipment with electronics, like VFD's, needs a hard ground going back to the feed or distribution transformer.  A hard ground, as I recall, is one that has less than 25 ohms resistance.

    This also means that if you are having intermittent faults on your electronic equipment on your laundry machinery, you'll want to check the grounds, ground bus, and associated wiring first; that means all the way to the transformer if necessary.  All ground terminals and connections want to be dog tight.  BTW, a conduit ground is not sufficient for VFD equipped machinery, a properly sized copper ground wire is sufficient.
    Jim Allen
    Chief Burro

    ------------------------------
    Jim Allen
    Potential Investor
    VIP Laundry
    Orange CA

    Potential InvestorVIP LaundryVIP LaundryJimAllenVIP LaundryVIP Laundry
    ------------------------------



  • 16.  RE: 3 phase vs 1 phase

    Posted 23 days ago
    Jim
    Perhaps you have an idea about a problem I have? I have 20 year old S.Q. washers. Every time there is a problem with the power several of these end up with an err. They say E pr. What that has to do with the pressure switch I have no idea. If the door is closed and latched they are less likely to go into err. Any time there is lightning or momentary interruption (like when there are high winds) this happens. I have very good surge and spike protection at the service entrance.
    I have wondered about a ground loop as two sub panels that sit side by side have different lengths of wire as one goes directly to the main panel under the slab and the other goes outside then to main panel.
    I have been dealing with this for ten years. Any thoughts?

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    Curt Harrington

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  • 17.  RE: 3 phase vs 1 phase

    Posted 23 days ago
    I have a bunch of '96 EC's.  When I get a power disruption, mine goto E:dr, for a drain error.  Its interesting because they will do this ONLY if left idle for an hour or so.  During the day, they get used and no issue.

    I haven't paid attention to whether the door is open/closed.

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    Timothy Foster
    Multi-Store Owner/ Employee
    Toledo
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  • 18.  RE: 3 phase vs 1 phase

    Posted 23 days ago
    Jim,

    Your information is somewhat priceless in terms of some of us operators finding solutions to emi efi nightmares.  We had a very challenging situation where I assumed that I could do all my testing of our Wasco Gen4 low voltage control update in the back room & not on the bulkhead.  A device that helped us after on the bulkhead was this: https://www.walmart.com/ip/SMART-SENSOR-Handheld-Mini-Digital-LCD-EMF-Tester-Electromagnetic-Field-Radiation-Detector-Meter/552958772?wmlspartner=wlpa&selectedSellerId=973&adid=22222222227095566003&wmlspartner=wmtlabs&wl0=&wl1=g&wl2=c&wl3=216268632932&wl4=pla-347533217180&wl5=9020931&wl6=&wl7=&wl8=&wl9=pla&wl10=113148614&wl11=online&wl12=552958772&wl13=&veh=sem  Why? it showed the unbelievable large amount of emf - elf coming from the mechanical timer motors.  Relocating the brand new pcb & using a more industrial duty pcb seems to now be 100%.  Phu Tran got us on the right track by testing the low voltage with battery only to see if some problems were from the electrical supply & there were.  It seems like the "ripple" rating of the power supplies & within the pcbs are critical for the the emi - elf problem prevention.

    Based on our experience setting up our PLC - Touchscreen 2 stall dog wash with the help of a very young budding electrical control engineer ... we learned (hard knocks way) that the following similar ferrules can help with making sure the connections are solid to prevent not just intermittent but like you say it can also cause EMI - ELF problems.
    https://www.digikey.com/product-detail/en/american-electrical-inc/1181010/288-1015-ND/266380

    On our ultra high g-force extractor project we insisted upon special tool-less connections on the safety certified 30+ led relays that were "vibration proof also.

    I remember talking to a JST representative about possibly using 20 ga wire where 22 ga was specified with their specified special crimper & quick disconnects.  He said in a very passionate way "absolutely not" unless you want to "gamble" on connections not 100% which for delicate electronics is critical.  Jim here shed further light on why.

    One more ding (Brooklyn accent?)... like the Peter Falk Columbo Detective Character would say ... It is not what the geniuses out there in STEM related learning environments tell you ... it can be what they DON'T tell you.  For example prototype boards are being sold with breadboard kits that really need more solid connections even on the prototyping level.  I had some old seismograph crew wiring laying around ... 100% copper ... tight fit for the in & out ports of the prototype pcbs ... that also was a life-saver.  I can just see some young enthusiastic boy or girl STEM kids getting so frustrated with some of the STEM crap out there that they never ever want to have anything to do with engineering again in their whole life.  Except giving huge engineering firms a blank check along with giving blank checks to the "100% cashless" "100% electronic voting" & the creating "dollar coin impediments" crowd & the latest generation of mobsters who have gone on record of saying they no longer need to "mug people" because of the "easy pickings' from the "100% cashless phone app crowd"!!!!  I am almost "out of breath" not quite though.

    Thanks again Jim for clarifying to a great extent what I kind of already knew but was having trouble articulating!

    No... no ... no ... none of us are vulnerable to the "shutting down of key electronics" by "master sabotagers" no no no ... say too many in varying states of "denial" & "unhealthy lack of skepticism" including politicians, clerics & some media people who have been known to go into "crap" mode from time to time.








    ------------------------------
    Michael Walsh www.kingkoin.com
    Store Owner/ Employee
    King Koin Laundry, Car n Dog Wash
    Bismarck ND
    ------------------------------



  • 19.  RE: 3 phase vs 1 phase

    Posted 14 days ago
    Michael brings up a great point about how frustrating emi-rfi problems can be.  However, I fought any number of those over the years and won every single time. Persistence is the key to beating them. In general order of highest priority:
    1. Check grounds and ground connections, they must be tight, home run grounds are better than grounds that 'pick up' other circuits along the way. Picking up means that other machines or equipments are tied to that same ground wire.  When this is the case, noise or faults on the other equipment can momentarily raise the voltage present on the ground wire.  Generally, ground resistance less than 25 ohms, as I recall, is preferred.  If you can get down to 5 ohms you're doing quite well. Ground testers can be quite expensive, look on the Grainger website to see, so if you suspect a ground problem or ground loop, call a professional to test it for you.  But do your homework first.  Floating conduits are a no-no.  A floating conduit is one that has come loose on one or both ends and now is being supported by the wire.  Ground connections always want to be dog tight.
    2. Use good wiring practices always.  Use field canceling practices wherever possible.  Tie wrap noisy parallel conductors together, keep power circuits away from signal and control circuits, put lids and covers back on boxes and compartments, make sure a VFD powered motor has a ground wire connected to the motor frame, use zero-crossing SS relays if possible, replace motor starter contacts or the entire contactors periodically, when replacing or rerouting wiring follow the original path. Motor starter contacts often will get very noisy before they fail.  That's because they have been subjected to substantial arcing and the contacts inside are heavily pitted.
    3. Be aware that poppet type solenoid valves like the water valves on almost all washers have a very high very short inrush current that will induce currents (and voltage) in nearby conductors. Ditto across-the-line motor starters and contactors.  This is because they have a very high rate of current rise on power up. In general, anything with a coil of wire in it will make noise when it is powered up.  For solenoid valves and motor starters, you might see 4-5 amps of pickup current, depending on how fast your meter is, with a holding current of 0.1 to 0.5 amps. A properly placed capacitor or MOV, metal oxide varistor, will substantially reduce some of this noise and they are cheap and easy to install.
    4. Noise should be stopped at the source, if at all possible, and not where it is causing trouble.  So if your controller goes into fault every time the HW valve is turned on, then the HW valve is making noise that is crashing, or locking up, the controller.  You would then want to put an MOV across the coil terminals to stop the noise at the source. That failing, you would want to put a line filter on the incoming power, usually 120 VAC or 24 VAC, at the controller.  Note that if a given board has incoming noise protection on it, the noise protection, or filtering, may have been degraded over a period of time due to chronic noise either on the line or in the air.  In the case here of the hot water valve, a suitable MOV would be rated 300V and 20 Joules.  These are available at Newark or any number of electronic components outlets.  Line filters, also available at Newark, might go for $40 or so while an MOV might be $2.  At the end of the day, if a given board still has problems then replace it or swap it and see if the problem moves or goes away.  The mechanical sequencer, timer, or rotating cam limit switch, whatever it is called, is inherently very noisy since it is doing a lot of switching of power circuits in short time periods.  They use plain, unprotected, unfiltered switches that are only designed to switch, not to prevent electrical noise.  The circuit diagrams for the machine will show if it is easy to apply a filter to the incoming power at the timer.  More later.
    Jim Allen
    Chief Burro

    ------------------------------
    Jim Allen
    Potential Investor
    VIP Laundry
    Orange CA

    Potential InvestorVIP LaundryVIP LaundryJimAllenVIP LaundryVIP Laundry
    ------------------------------



  • 20.  RE: 3 phase vs 1 phase

    Posted 13 days ago
    I had some emi-efi headaches with some early computerized dryers a while back...ADC-285's to be specific.

    Not knowing much about line noise, I figured it had to be poor grounding, so at first I took the easy way out. I ran some zip cord and bridged all the dryers together to create a common ground. I also tightened all the connections in my breaker panel. That helped only a little. There was simply too much "noise" on the old wiring in my store.

    What needed to be done was to run a separate dedicated ground wire all the way from my main water line coming into the building.
    If that didn't work, I was prepared to drive a separate ground rod into the ground just for those dryers.

    I was not aware of using a sensors or a noise filter at that time, but thanks for your info Michael & Jim.

    BTW, when I was stringing the zip cord from one dryer cabinet to another, I actually saw a little minor sparking from one cabinet to another. I figured it was electrical leakage, but I had no idea where to start to hunt down the source.
    Leakage can do no good. At the least, I figure it was costing me money, similar to having a faucet drip.

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    Paulie B
    Multiple Mat Owner since 1976
    New York City, NY
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  • 21.  RE: 3 phase vs 1 phase

    Posted 12 days ago
    Paulie, the arcing that you saw may have been static or it may have been currents leaking to the dryer frame from somewhere inside the cabinet.  Either way, it is an indication that the incoming ground from the panel to the dryer is somehow insufficient.  Ideally, you want a separate and dedicated ground wire for each dryer in each conduit.  If possible, you do not want your equipment sharing grounds, ditto the neutral wire if you're using 120 VAC.

    All, lighting circuits can share neutrals if they are well balanced across all 3 phases.  BTW, a perfectly balanced and equal 3 phase lighting system will have how many amps on the neutral?  Let's say you have 10 fixtures all flowing 1 amp of current on each of 3 phases and all are 120 VAC.  That is 10 amps on A phase, 10 amps on B phase, and 10 amps on C phase.  How many amps appear on the neutral?  This is somewhat of trick question.  How many amperes of current appear on the neutral?  The correct answer is 0, yes zero.  The logical answer is 0 and the trigonometric answer is 0.

    Again, ground circuits are very important on any machine with electronics on board.  Ground connections should be dog tight, should be home run where possible, and should be below 25 ohms, as I recall, to earth.  This will keep the electronics quiet.  In the old days, conduit grounds where quite sufficient because all machines were linear loads.  Today, copper grounds from machinery to the earth, through the conduits and panels, are required to keep the electronics quiet.  I'll do some refresher reading to verify the 25 ohm number, but that's what I remember.  BTW, your standard neighborhood electrician may not fully understand any grounding issues that you may be having.
    Jim Allen
    Chief Burro
    VIP Coin Laundry

    ------------------------------
    Jim Allen
    Potential Investor
    VIP Laundry
    Orange CA

    Potential InvestorVIP LaundryVIP LaundryJimAllenVIP LaundryVIP Laundry
    ------------------------------



  • 22.  RE: 3 phase vs 1 phase

    Posted 12 days ago
    I forgot to mention that you can run a common ground from machine to machine to panel ground bus.  The trick is to not cut or break the wire, if possible, and to use 1 size larger ground than you have feed circuit.  Thus, if you have ungrounded #12 feed circuits going to each dryer then you would want to use a #10 ​​insulated ground wire and jump from machine to machine to panel without, if possible, cutting the wire.

    We should probably start a separate thread on grounding issues.

    Jim Allen
    Chief Burro

    ------------------------------
    Jim Allen
    Potential Investor
    VIP Laundry
    Orange CA

    Potential InvestorVIP LaundryVIP LaundryJimAllenVIP LaundryVIP Laundry
    ------------------------------



  • 23.  RE: 3 phase vs 1 phase

    Posted 10 days ago
    Michael,

    I'll look into that device that you noted above, sounds very interesting.

    All, after completing work on a machine, panel and box covers need to be put back on properly with at least a screw securing it. Say what?  One screw?  What will that do?  RFI travels in all directions, both in to and out of a given device, so covers need to be restored.  The screw electrically connects the cover to the body of the box, thus grounding it as far as the RFI noise is concerned.  That is, a box cover may be getting noise induced into it which then turns into voltage, the screw will provide a good path to drain the noise away to the machine frame then into the ground wire coming into the machine.

    I mentioned earlier that older pcb's often were noise sensitive and often needed field work to quiet them.  Newer pcb's are far better designed, however, their noise protection can become degraded over time due to high levels of emi-rfi.  This means that proving a noise issue and solving a particular problem may mean swapping boards. If the original problem seemed to be caused by noise and swapping boards solved the apparent noise problem, then that board will likely need repair.

    A point about ground wires from the Ugly's book: If the feed wires to a machine are #12 for a 20 amp circuit breaker then the ground wire needs also to be #12. Number 12 wire has 1.93 ohms of resistance per 1000 ft of wire.  Number 10 wire, which is good for up to 60 amp circuit breakers, has 1.21 ohms of resistance per 1000 ft.  This is a 37% reduction in resistance by going up in size 1 increment from number 12 to number 10 (1.93-1.21)/1.93=37.3%.

    Jim Allen
    Chief Burro
    VIP Coin Laundry
    ​​​

    ------------------------------
    Jim Allen
    Potential Investor
    VIP Laundry
    Orange CA

    Potential InvestorVIP LaundryVIP LaundryJimAllenVIP LaundryVIP Laundry
    ------------------------------



  • 24.  RE: 3 phase vs 1 phase

    Posted 9 days ago
    OMG OMG OMG !!!!
    The guy posting this thread had a simple Question. HIS head must be spinning, reading this.

    TAKE THE GODFATHERS ADVICE !!!

    NO ONE ONE HERE IS A LICENSED MASTER ELECTRICIAN.

    Call your local reputable electrician office and talk on the phone with the head or pay them to visit you to seek their input.
    OR talk to your Dist office, someone who has knowledge with doing multiple mats, what is their 2cents.

    SAVE YOUR TIME, MONEY AND HEADACHE AND GET A MASTER ELECTRICIAN TO COME BY.

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    ORIGINAL GODFATHER
    ------------------------------