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Switch Wiring 3ph vs 1 ph

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Forum topic by DaveMonti posted 02-22-2015 07:18 PM 747 views 0 times favorited 16 replies Add to Favorites Watch
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DaveMonti

5 posts in 744 days


02-22-2015 07:18 PM

Topic tags/keywords: pm66 electric switch

Hello folks,

I have a simple question regarding switch wiring. I have a PM66 for which I recently bought a single phase motor. The switch that came with the saw is wired for 3 phase.

There are 2 wiring diagrams inside the switch cover. One indicates “Single Phase Terminal Jumper Power Source” while the other diagram indicates “Single-Phase Three-Phase Power Source”. I’ve attempted to attach a picture (hope it worked) of the diagrams. The switch is currently wired for “Single-Phase Three-Phase Power Source” and originally I had a 3 phase motor on the saw.

My question is essentially “Is the current wiring setup for Single-Phase Three Phase Power Source correct for my new Single Phase Motor or do I have to rewire it to reflect the Single-Phase Terminal Jumper Power Source diagram?”

Thanks for any help!

Dave


16 replies so far

View exelectrician's profile

exelectrician

2327 posts in 1891 days


#1 posted 02-22-2015 07:35 PM

Yes – Follow the instructions printed on the name plate. You could download the manual and follow more detailed guidance found there.

-- Love thy neighbour as thyself

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DaveMonti

5 posts in 744 days


#2 posted 02-22-2015 07:46 PM

Thanks exelectrician,
When you say “Yes”, do you mean the current wiring is of the switch is good for Single Phase AND Three Phase?
I have looked online for explanations, a manual for the switch, etc., but see nothing that will give me an answer. I understand how to hook the motor and power supply up to the switch, but I am only questioning the internal wiring of the mag switch itself.
Thanks again!
Dave

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klassenl

170 posts in 2122 days


#3 posted 02-22-2015 08:10 PM

Both of those diagrams are correct.

-- When questioned about using glue on a garbage bin I responded, "Wood working is about good technique and lots of glue........I have the glue part down."

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exelectrician

2327 posts in 1891 days


#4 posted 02-22-2015 09:30 PM

As far as I can tell the diagrams refer to 220V three phase (in which case you would have a three phase motor installed) – Or 220Volt single phase ( single phase motor installed ) ... Do not put single phase power onto a three phase motor or three phase power onto a single phase motor. Unless you want to let the smoke out permanently, ha ha.

-- Love thy neighbour as thyself

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MrUnix

4224 posts in 1662 days


#5 posted 02-22-2015 09:38 PM

Also, it you are replacing a 3 phase motor with a single phase, make sure you verify the mag starter and other associated control circuitry will work with what you are installing.

Cheers,
Brad

-- Brad in FL - To be old and wise, you must first be young and stupid

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DaveMonti

5 posts in 744 days


#6 posted 02-22-2015 10:48 PM

Thanks everyone!
I am wiring single phase 220 V to my saw, which I just bought a 3 HP 220 V Single Phase motor for.
Brad, I am trying to see if the mag starter is correct. The internal wiring on the mag switch is wired like the diagram on the right in the picture and this starter was in use in 3 phase 220 V. However, now that I am using a single phase motor, I am trying to figure out if I need to change the internal wiring on the mag starter/switch or if I can keep it the way it is currently wired. Both the Left and Right wiring diagram in the photo indicate Single Phase., with the right diagram also indicating 3 Phase. So, I left the mag starter as it was wired (internally) and will give it a shot as others have said both diagrams are correct (for single phase, I’m assuming!). I do not have 3 phase power in my shop, so no danger there.
Thanks to everyone for your responses!

Thanks!
Dave

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REO

889 posts in 1537 days


#7 posted 02-23-2015 12:50 AM

The only difference electrically is that they are doubling up the contacts for each leg in the diagram on the left. If wired per the diagram either will work. be sure to omit connecting incoming line to terminal #2 at the top. It shows it the correct way.

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TopamaxSurvivor

17671 posts in 3139 days


#8 posted 02-23-2015 02:56 AM

Just connect your single phase 220 and the motor leads to the outside poles of the motor starter, forget the center pole. It should work just fine. ;-)

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

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MrUnix

4224 posts in 1662 days


#9 posted 02-23-2015 03:05 AM

I was thinking more about the heater (overload protection).. most saws need the mag switch/heater to be matched to the motor and based on current draw. Might not be necessary on that saw though..

Cheers,
Brad

-- Brad in FL - To be old and wise, you must first be young and stupid

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TopamaxSurvivor

17671 posts in 3139 days


#10 posted 02-23-2015 03:08 AM



I was thinking more about the heater (overload protection).. most saws need the mag switch/heater to be matched to the motor and based on current draw. Might not be necessary on that saw though..

Cheers,
Brad

- MrUnix

They should be checked and adjusted or changed to match the motor. Unfortunately, in my experience, most never are. The overloads are usually set too high and motors are damaged before they trip ;-(

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

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REO

889 posts in 1537 days


#11 posted 02-23-2015 03:33 AM

Looking at the schems there are no heaters or secondary OL protection

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MrUnix

4224 posts in 1662 days


#12 posted 02-23-2015 04:12 AM


Looking at the schems there are no heaters or secondary OL protection

Well, it’s gotta be somewhere ;)

I can’t really read the schematic in the photo, but I did notice that replacement switches for the PM are sized for specific motor sizes.. such as this one that is listed as 3HP 230V Single Phase ONLY :

If the machine was originally a three phase, I seriously doubt the motor had built in overload protection, but anything is possible I guess. Most of the machines I’ve used or worked on have a LVC switch that runs over to a box on the back or side that contains the mag switch and overload heater. I’ve also seen them with a dial where you can select the amp draw for overload. Lots of variations, so it’s kind of hard to tell what that particular saw has.

This is an interesting read: http://wiki.vintagemachinery.org/Magnetic%20Starters%20Explained.ashx
That goes into great detail about mag switches, overload heaters and other good stuff.

Cheers,
Brad

-- Brad in FL - To be old and wise, you must first be young and stupid

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TopamaxSurvivor

17671 posts in 3139 days


#13 posted 02-23-2015 05:23 AM


Looking at the schems there are no heaters or secondary OL protection

- REO

The motor probably has internal overload protection. Edit: That diagram has the OLs. They are shown mechanically interlocked with the “stop” button.

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

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DaveMonti

5 posts in 744 days


#14 posted 02-23-2015 06:29 AM

Thanks folks,
The single phase motor I’m installing has internal overload protection. The switch, being that it can be used for three phase, does have OL protection as well. It has a small dial to set OL amps. I’ll be sure to set it at or below the FLA of the new motor.
Thanks again gents!

Dave

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REO

889 posts in 1537 days


#15 posted 02-23-2015 10:40 AM

That depiction is new to me. I am used to the “hooks” in a shem or a dotted box with OL and a rounded arrow for the variable style. See you can teach and old dog to read the new stuff lol

showing 1 through 15 of 16 replies

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