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It would be worth it to get some help sorting this out.
That gray box with a knife switch is Something Not Normally Found On Saws, if you want to know what it is. Those three boxes below it could be filled with Electrical Knock You On Your butt.
This saw might have been set up with a phase converter in its past location, given that one leg is marked with blue tape. That might mean "Generated leg", and is not used to power the magnetic starter. It also might mean the installer was color blind.
If you have three phase power in the shop, you might be able to just remove any converter stuff on the saw, put the right plug on the saw, and run it. Not burning stuff up by using the wrong voltage and phases would be worth hiring an electrician. Confusing a white hot leg with a neutral can be a one off mistake.
WH
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(08-02-2017, 05:51 AM)WilliamHodge Wrote: It would be worth it to get some help sorting this out.
That gray box with a knife switch is Something Not Normally Found On Saws, if you want to know what it is. Those three boxes below it could be filled with Electrical Knock You On Your butt.
This saw might have been set up with a phase converter in its past location, given that one leg is marked with blue tape. That might mean "Generated leg", and is not used to power the magnetic starter. It also might mean the installer was color blind.
If you have three phase power in the shop, you might be able to just remove any converter stuff on the saw, put the right plug on the saw, and run it. Not burning stuff up by using the wrong voltage and phases would be worth hiring an electrician. Confusing a white hot leg with a neutral can be a one off mistake.
WH
electricity is colorblind
Marking a white wire with blue tape indicated to the installer the leg is no longer a neutral wire but an energized wire
I seriously doubt the saw was on a phase converter considering it was in a school...... most schools have 3 phase power supplied
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what are the transformer-like things (gray boxes) likely to be? All the level-shifting transformers I have seen are 3 phase.
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08-02-2017, 10:46 AM
(This post was last modified: 08-02-2017, 10:47 AM by TDKPE.)
(08-02-2017, 10:03 AM)EricU Wrote: what are the transformer-like things (gray boxes) likely to be? All the level-shifting transformers I have seen are 3 phase.
You can connect three single-phase transformers in series or parallel for either delta or y-connected input, but why would you? That's usually done at the utility level, not on a piece of equipment unless it's factory built, and especially not at the electrician making the connection level.
Tom
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08-02-2017, 02:06 PM
(This post was last modified: 08-02-2017, 02:08 PM by fredhargis.)
I'd really consider putting a VFD on it, it will be cheaper than an RPC and work really well. Here's some stuff that was over at OWWM on this very question. It's going to cost you some more to get functional, but you will have a lifetime saw. Notice they (some of them) are running 5 HP motors on a 3 HP VFD with no ill effects.
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(08-02-2017, 10:46 AM)TDKPE Wrote: You can connect three single-phase transformers in series or parallel for either delta or y-connected input, but why would you? That's usually done at the utility level, not on a piece of equipment unless it's factory built, and especially not at the electrician making the connection level.
I assume they had the wrong incoming voltage for the motor. For a while there in our building, they wanted us to hook up to the 480, then they realized that was silly because the 480 was derived from a step-up transformer. But to get 240, they had to run a wire upstairs instead of just out into the hallway like the 480. Worked out for me , but next door there are a batch of step down transformers.
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If you have 3 phase in the building it may be worth swapping out the starter for an appropriate starter. As it was mentioned above plently of info over at OWWM.
If no 3 phase consider swapping out the motor and starter to single phase. eBay is your friend for this. I swapped out my motor and starter for 275. If the motor doesn't have overload protection you need the overload via the starter. The motor is cheaper but the starter will be a bit more.
Don
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Call me an old sissy if you will, but this is NOT the standard electrical hook up for a PM 66. If you aren't already aware of what it all means, then it's time to engage an electrician, who does know how to sort it out. It's possible someone could walk you through it on line, but if you miss something, and it all goes South with the end result being an electrical fire I can tell you your insurance company will sort it out, and if you mess it up, you may also not be insured for damages. Don gave very good advice about the swap out to a single phase motor, and you definitely DO NOT need 5 HP, 3 HP runs most of the cab saws out there today.
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Is there a magnetic starter anywhere on that saw? That would be something with a momentary pushbutton that starts the motor till another button is pressed to stop it? I doubt that knife switch is what they used constantly to do that, though I may be wrong.
In any event, if it were my saw, there would be two options and both would require you to get a mag starter of some sort as the primary means of starting it up. As Fred suggested, a VFD would probably work just fine. Can't speak to using one rated for 3hp on a 5hp motor, but if you set the ramp up time for a few seconds, I doubt the motor would ever draw more than the vfd was capable of producing. You can wire remote switches off the VFD or use the buttons on the front to start and stop the motor after the VFD is powered up.
Second option would be to replace the motor with a single phase. That saw uses a C-face motor, fairly common. I would think you could pick up a 3hp version that would fit for 2-300 used, maybe cheaper. You would have to pop the table off to get access, but that would be a simpler solution electrically. Post a WTB here or over on owwm.org and I'll bet you find one quick enough.
Cost wise, it may be a toss up between either option, the VFD may run you upwards of 200 if you opt for the 3hp version. Over 3hp, they tend to get very pricey.
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I have been assuming it has the standard pushbutton control on the front and we just haven't seen it because there are no pics of the full saw. The disconnect and transformers are just feeding into that. If that isn't the case, get a manual and recreate it. But I don't see how they were using the saw with only a disconnect as a control, that sounds insane
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