Any one familiar with an older Grizzly 20" disc sander?

[Greg McClurg]

I just picked up a used Grizzly 20" disc sander model DS-20. The tag indicates it is a 110/220 2hp and has a date of 1987. I've searched the internet and can't come up with any information on this tool. I am wondering if anyone has one or knows anything about it. Of course someone having a manual on it would be great.

Thanks,
Greg

[Matt Day]

Did you call Grizzly and ask?

[Greg McClurg]

Matt,

It was too late this evening to call, but I did check their website for manuals, which didn't have it listed.

[Van Huskey]

That's a copy of the "standard" 20" sander made by a lot of US and Asian manufacturers over the years. Anything in particular you need to know or is it just for information purposes?

[Greg McClurg]

Van,

It's basically for information purposes. However, initially I need to know some info regarding the wiring. The machine does not have a plug as it was direct wired. Not being an electrician I don't know if it is set up for 110 or 220. I thought the manual may have the wiring diagram for each.

[Van Huskey]

Van,

It's basically for information purposes. However, initially I need to know some info regarding the wiring. The machine does not have a plug as it was direct wired. Not being an electrician I don't know if it is set up for 110 or 220. I thought the manual may have the wiring diagram for each.


Almost every 120/240 motor I have been inside looks like this.

You will have 3 wires coming into the motor's junction from the "outside" and 4 wires coming into the motor's junction box from inside the motor. The outside wires will usually be black white and green. This doesn't really matter but just identify the ground (usually green) attached to the metal of the box. Now see what the other two wires (black/white) are connected to in terms of the ones coming in from the motor itself. If each of the two wires from outside are each connected to 2 wires coming from the motor (2 sets of 3 wires tied together) then it is wired for 120v. If each of the outside wires is wired to just 1 wire each from the motor and the other two motor wires are tied together then it is wired for 240v (3 sets of 2 wires tied together). My father just used to tell me to count the wire nuts, 2 and it is 120V and 3 and it is 240v. While it may not work for every motor I have yet to be stumped by a US/Asian single phase motor that was 120v/240v but I am sure there are ones that would.


PS if you want to wire it to the other voltage post the wire colors (and the current connection scheme) from the motor and me or someone else can likely figure it out, especially if it is a "standard" red yellow black and gray or numbered 1-4.

[Greg McClurg]

Thanks Van. I'll look at it tomorrow evening. It sounds like it should be very straight forward.

[Van Huskey]

Thanks Van. I'll look at it tomorrow evening. It sounds like it should be very straight forward.

It is far more complicated to type than it is to actually "see".

[Greg McClurg]

Well, it wasn't as clear as I had hoped it would be. I'm trying to tell if this is wired for 110 or 220. Can you tell from these pictures? The switch is the first picture, and also shows in the second picture.
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[Van Huskey]

OK ASSUMING everything is wired correctly and it ran when wired like this I am 99% sure it is wired for 240v. That is based on the assumption that the red and blue wires coming from the motor are tied together but I can't see how they are terminated from the picture, if they aren't tied together but are tied, one each, to the black and yellow wires from inside the motor then it is 120V. I need to know how those two wires are terminated and would really like to do a continuity trace on all the wires through the switch and into the motor. But, I would feel comfortable making the call on MY equipment knowing what is going on with the blue and red wire.

[Greg McClurg]

Van,
The first photo is on the motor. The 3 wires in the top left are wired together and are #1, #3, and #5...look like blue and 2 white. The top row of screws are from the motor and are L to R, Red #2, blank, Yellow #6, and Black #4. Bottom row are coming from the switch Green, blank, Red, White.

The second photo is the switch. On the left side are the wires coming from the motor. Top to bottom are White, Black, Green. Middle row are from the outlet T to B are White, Black, and Red. The red is from the motor. The green from the outlet is fastened to the frame (ground). The right row (yellow wires) are jumpers.

Does that help?
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[Van Huskey]

OK I got it but lemme run through my logic so someone else might see an issue in it.

First, I tried to visually trace the power through the switch but not knowing how the switch operates and with the 3 jumpers and not knowing where one of the jumpers and the ground wire connect it was a lost cause. 2 minutes with a multimeter or forever looking at the pictures.

In any event we have 4 wires coming from the switch to the motor. Both the green and the black wire are terminated together bottom left of the motor terminal strip so they "have" to be grounds. So the red and white are either our hot legs (240V) or our hot leg and common (120V). The red wire #2 is the motor ground since instead of the switch side grounding to metal it is terminated to the terminal strip and continues through the red wire to ground the motor.

Given the way #6 black and #4 red are wired by themselves to the white and red from the motor side and the other 3 wires from the motor are tied together I am 99.9 percent sure it is 240v wired.

Now keep in mind my 99.9% is coming from a less than 50% expert in motor wiring, so you need to keep that in mind when you calculate YOUR odds. If it were mine I without any chance of finding a wiring diagram I would wire it for 240 and cross my fingers... BUT I really hate to suggest you do it. Since there have been no there have been no other takers here and you have good pictures you could always take your query to Practicalmachinist or maybe OWWM but they don't really like import machines there and see if someone or the group can work their way through it they may want you to test the resistance of the windings to get a clearer picture.

Sorry I can't be 100% but that is my best shot at it.

[Greg McClurg]

Thanks for your help Van. It probably will be after the holidays before I'll get a good chance to study this more, but I'll post the end result when i get one.

[David L Morse]

I think you have a reversing switch and the Red and Green wires are involved with the start winding. At first glance it looks like the motor lead numbering is non-standard. I'll look into this more when I have time later unless someone else clarifies it first. My initial guess at voltage agrees with Van, i.e., 240V.

[David L Morse]

Ok, I'm back and have had a close look at the photos. You have a reversing switch and the motor is wired for 240V.

The internals of a reversing switch are very straight forward. In the "off" position nothing is connected. There are two "on" positions, one for clockwise and the other for counter clockwise rotation. In one of those positions each center terminal is connected to the terminal to it's left (referring to the photo). The other position then of course connects it to the one on the right.

Starting at the top of the switch we have the White wire from the supply connected to the center terminal. There's a jumper wire connecting the left side to the right side. The White wire feeding the motor is connected to the left side and, via the jumper to the right side also. So regardless which direction is chosen the two White wires are connected when the switch is on.

The Black wires duplicate the switching arrangement of the White wires so when the switch is "on" the supply goes straight through to the motor on the Black and White wires in the four wire cable between the switch and motor.

The third pole of the switch has the Red wire from the four wire cable connected to the center terminal. The right side terminal has a jumper going up to the top terminal and so is connected to the White wire from the four wire cable. The left terminal has the Green wire which is connected to the Black wire in the motor box. The net result of all these connections is the Red wire connecting to either the Black wire or the White wire depending upon which rotation direction is chosen. (all of the colors in this paragraph refer to the four wire cable)

To reverse the direction of a single phase motor the start winding polarity with respect to the run winding must be reversed. For a dual voltage motor in low voltage configuration both leads of the start winding to be changed thus requiring four wires to the switch and two poles of switching. When wired for high voltage only three wires and one pole are needed.

The three wires from inside the motor that are connected together is what you would see for high voltage operation. That connection is one lead from each of the run windings and start circuit.

What doesn't make sense to me is the motor lead identification. Neither the colors nor the numbers match the NEMA marking requirements. I hope you don't want to convert this motor to 120V operation. That could be an adventure.

[Greg McClurg]

Thanks David for your assistance. As I originally stated the sander doesn't have a plug on it so I just needed to know which to add...a 110 or a 220. I'm perfectly fine with leaving it as 240.

[Greg McClurg]

Well I plugged it in, threw the switch, and blew the breaker. Any thoughts?

[David L Morse]

That is of course exactly what you would expect if the motor were wired for 120V and you applied 240V. I really don't think that's the situation here based upon the photos you provided.

A couple of questions before I head for the bedroom:

Are you certain that the device was operating correctly before you acquired it?

Do you have an analog volt-ohm meter?

I'm going to bed now but I'll think about this some more in the morning.

[Greg McClurg]

Thanks David

I don't know that it was working prior to purchasing, but they said it worked.
I do have an analog volt-ohm meter.

[David L Morse]

How long did it take for the breaker to trip? Was it instantaneous, feeling almost like the switch and breaker were mechanically connected? Or, was there a brief pause with maybe some hum from the motor? Or did it take several seconds?

[Greg McClurg]

David,

It was almost instantaneous. I switched the plug this morning to 110 and tried it it hummed and started to turn then blew the breaker, but it took several seconds before that happened. I stopped at that point. The inside of the cover has the wiring which I will try tonight to get a picture and post it.