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Forum topic by ABrock posted 04-15-2016 10:38 PM 747 views 0 times favorited 13 replies Add to Favorites Watch
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ABrock

6 posts in 663 days


04-15-2016 10:38 PM

I bought this Powermatic 66 saw on Craigslist. It is a 3 phase machine. I am unfamiliar with 3 phase and am trying to figure out what this gray box is in the back of the saw. It is made by Square D and has its own circuit breaker. Trying to figure out if this is normal for 3 phase or if this is some sort of converter. Thanks for any help.


13 replies so far

View TheFridge's profile

TheFridge

5765 posts in 948 days


#1 posted 04-15-2016 10:39 PM

Looks like the starter to me. Standard stuff.

-- Shooting down the walls of heartache. Bang bang. I am. The warrior.

View MrUnix's profile

MrUnix

4216 posts in 1661 days


#2 posted 04-15-2016 11:06 PM

Trying to figure out if this is normal for 3 phase or if this is some sort of converter.

Gotta see the insides to be sure… but unless it’s just a service disconnect (doubtful), then it’s normal for all cabinet saws, not just three phase ones… like the Fridge sez… it’s a starter. Typically consists of a control voltage transformer, magnetic contactor and overload protection (heaters). Besides power in and wiring to the motor, it should have three wires going from it to the control station (start/stop buttons) in front of the saw. To run it on standard single phase, get a VFD; then you can remove and re-sell the starter to recover some of the money. Keep the control station to use with the VFD.

Cheers,
Brad

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

View rick1955's profile

rick1955

258 posts in 893 days


#3 posted 04-16-2016 06:06 PM

As usual not enough. The front of the saw should a small box with an off and on push button. Show the plug. Most certainly the box you show is the starter/contactor. More info is better than less.

-- Working smarter with less tools is a true crafts person...

View JackDuren's profile

JackDuren

136 posts in 421 days


#4 posted 04-17-2016 02:41 AM

Wish you guys were closer. I just put a rebuilt 3hp single phase Baldor on craigslist for trade off a 66…

View runswithscissors's profile

runswithscissors

2183 posts in 1487 days


#5 posted 04-18-2016 05:34 AM

Very likely it is a magnetic switch, intended to cut power to the tool if you should have a power outage. That’s so the tool won’t start back up again on its own. There probably is a paddle switch or toggle at the operator’s end of the saw for normal on/off operation. I have no idea whether 3 phase and single phase devices are the same.

Mine has a reset button to activate things again. Oh, I bet that’s the black rectangle on the bottom there.

I replaced mine with a combination on/off magnetic switch (from Grizzly) when I had to service my motor recently.

-- I admit to being an adrenaline junky; fortunately, I'm very easily frightened

View MrUnix's profile

MrUnix

4216 posts in 1661 days


#6 posted 04-18-2016 06:14 AM

Very likely it is a magnetic switch, intended to cut power to the tool if you should have a power outage.

Actually, that’s just a side effect :) Starters provide two basic funcitons – a contactor (relay) to control the voltage going to the motor, with substantially larger contact points than a typical on/off switch provides, and to provide overload protection for the motor. The control station (start/stop) typically has momentary switches, with a normally closed stop button and normally open start button. Once the start button is pressed, it latches the contactor closed through the stop button, and will be held closed until the stop button is pressed (breaking the circuit). A power failure will do the same thing as pressing the stop button.

Newer machines have almost all gone to the cheaper IEC controls, which are no where near as robust and generally non-serviceable (NEMA starters can have their components replaced if needed). The same deal with those little mag switches as sold by Grizzly and others – and those don’t usually provide any overload protection at all – so unless your motor has a built in overload, they usually are not a good alternative.

Most starters can be used for either single or three phase operation – for single phase, you just don’t use the third leg. However, switching from three phase to single phase requires changing the overload protection to match the motor, and on some of those starters, finding appropriate heaters can prove very difficult or impossible.

Cheers,
Brad

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

View runswithscissors's profile

runswithscissors

2183 posts in 1487 days


#7 posted 04-18-2016 07:14 AM

See, if you’d answered the OP’s question before I tried to, I wouldn’t have ended up embarrassing myself by displaying the extent of my ignorance.

-- I admit to being an adrenaline junky; fortunately, I'm very easily frightened

View MrUnix's profile

MrUnix

4216 posts in 1661 days


#8 posted 04-18-2016 07:31 AM

See, if you’d answered the OP s question before I tried to, I wouldn’t have ended up embarrassing myself by displaying the extent of my ignorance.
- runswithscissors

LOL – I thought I had :)

No worries… the OP seems to have gone missing anyway.

Cheers,
Brad

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

View ABrock's profile

ABrock

6 posts in 663 days


#9 posted 04-18-2016 01:27 PM

Thanks for all the input. Just curious, what do you think this saw would sell for? Not sure if I wanna sell it and get something I can run here without any converters.

View unbob's profile

unbob

718 posts in 1365 days


#10 posted 04-18-2016 02:56 PM

The 66 with a Bies fence in that condition would go for $1200 in my area. Half that or so for a Unisaw.

View MrUnix's profile

MrUnix

4216 posts in 1661 days


#11 posted 04-20-2016 06:37 AM

Not sure if I wanna sell it and get something I can run here without any converters.
- ABrock

I wouldn’t get rid of that PM66 – it’s a beast of a machine and will be the last saw you ever need to buy. Splurge the extra $160 or so and get a VFD. Three phase motors are bullet proof, more robust, quieter and more efficient than their single phase counterparts. With the VFD you will also get all sorts of benefits you will never have with a single phase machine – slow start, electronic breaking, over-torquing, variable speed (from about 10% up to 200+% of rated), trivial wiring for start/stop and emergency stop if desired, constant speed/torque independent of load, etc… etc… etc… Mount it on the saw and it’s plug-n-play with the 240v single phase outlet in your shop. Sell the starter on there now (it won’t be needed any longer) and you can recover most, or maybe even all of what you paid for the VFD.

Cheers,
Brad

PS: Wiring a VFD is also trivial… the hardest part about using one is figuring out where to mount it :)

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

View upinflames's profile

upinflames

209 posts in 1624 days


#12 posted 04-20-2016 12:33 PM

You could spend a little more and just go with a new single phase, $355 with free shipping. What ever you choose, VFD or new, that saw will outlast you, I’ve tried to wear one out, haven’t succeeded yet.

Cheapest out there at the moment:

https://www.zoro.com/leeson-saw-motor-3-hp-3450-rpm-230v-12082400/i/G3440236/

View ABrock's profile

ABrock

6 posts in 663 days


#13 posted 04-20-2016 12:41 PM

thanks for info. Maybe I will keep it.
Which vfd is the best or does it matter? Tied looking them up yesterday but seemed like there were a ton of options.

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