DC motor and controller question.

anvilring

anvilring

Joined
Nov 29, 2000
Messages
2,869
Here is a shot of the controller box on/for the 1hp I currently have, someone ask for pics of it. I have no idea if it's hooked up right or not. It seems to have very little power even for a 1hp. Below are pics/links of the 1.5hp DC motor I have that might replace it, and a DC controller that "might" work/help in either case (perhaps to replace the old controller I have now). Am I on the right track? The 1.5hp motor has a huge (7/8ths?) shaft... where could I get the current drive wheel milled out to fit it? And is that even a doable idea? I have nowhere around here I know of to do that. And if someone has a better idea for the controller, tell me where to find it please.

regards, mitch

20201006_113450 by rynegold, on Flickr

20201006_113433 by rynegold, on Flickr

20201006_112552 by rynegold, on Flickr

20201006_112606 by rynegold, on Flickr


https://www.ebay.com/itm/KB-Electro...-115-230VAC-KBMD-240D-0-75-1-5HP/323970854882

or this one:

https://motorsandcontrol.com/kb-ele...0hk-EFldBf0ezjDHi4ylPElAghwnqEiRoCl6MQAvD_BwE
 
How big of a drive wheel do you have? I just rigged up my DC grinder, with a 4" drive wheel. I had a machine shop bore it out to 7/8" for me
 
The drives you linked to are in NEMA 1 enclosures, you want NEMA 4. They will require 220V to run the 1.5 HP motor and an additional heat sink. The website also says that you will need a horsepower resistor. Do you have 220V available?

Do you know whether your drive or your 1 HP motor is causing the problems?

Your current drive may be able to run the 1.5 HP motor. Do you have a manual or the model number? There are different MM20000 drives, so the exact model is needed.
 
Did you check the brushes on the 1 HP motor? A loss of power could be caused by worn brushes. I mentioned this in your other thread, not sure if you saw it.
 
Yes, If you haven't replaced the brushes you should do that first. I was thinking you said you had done it in the other thread, but may have read it wrong.
 
I have not checked the bushings... I don't actually know how to access them for one thing. That said, where do you buy such as that? Replacement bushings that is?
My shop has only 120v, so no 220v available... guess I'll just try bushings first, a new controller second, and a new AC motor and controller last. This is really a good old machine so I want it repowered and to use it a lot. It also has an "offset" hard rubber top idler pully on the flat platen; I wonder why? I'll add a pic if anyone would like to see it. Seems it would be better as an all aluminum wheel w/a straight shaft into the wheel. The bottom flat platen wheel is hard rubber too but, a smaller diameter and a straight shaft.
 
Atlas Knife Company said:
How big of a drive wheel do you have? I just rigged up my DC grinder, with a 4" drive wheel. I had a machine shop bore it out to 7/8" for me
Click to expand...
Do you remember what they charged you for that? Just curious... What size motor are you running DC? and on what? 120v or 220v?
 
anvilring said:
I have not checked the bushings... I don't actually know how to access them for one thing. That said, where do you buy such as that? Replacement bushings that is?
My shop has only 120v, so no 220v available... guess I'll just try bushings first, a new controller second, and a new AC motor and controller last. This is really a good old machine so I want it repowered and to use it a lot. It also has an "offset" hard rubber top idler pully on the flat platen; I wonder why? I'll add a pic if anyone would like to see it. Seems it would be better as an all aluminum wheel w/a straight shaft into the wheel. The bottom flat platen wheel is hard rubber too but, a smaller diameter and a straight shaft.
Click to expand...
Brushes, not bushings. Motors use carbon brushes that are spring loaded. There should be some access panels towards the rear of the motor on both sides.
 
Without 220 V, you may not be able to run the 1.5 HP motor. The KB drive you linked to previously needs 220 V to run a 1.5 HP motor, and I suspect the MM20000 has a similar requirement, if it can even drive larger motors than the 1 HP that came with the grinder.

The best solution I am aware of to get the maximum out of 110 V is to use a 3-phase motor with a KBAC-27D drive to get 1.5 HP. It is expensive, though.
 
Here is a link to replacement brushes that show what the parts look like. They are not expensive. At the bottom of the page, they show brush caps. If you see something that looks like that on your motor, that's where the brushes will be.

When you take the brushes out, you can blow out the motor with clean dry air.
 
Sorry, right: brushes. I've seen/taken those out of a motor before (can't remember why). I'll look when I get home here in a while and take'em out, and take a pic of them. Oh and thanks for the brush link!
 
I tried to find the correct replacement brush part number for your motor but came up empty. You may have to call a place that sells the replacement parts if the brushes are bad.

The motor drawing I found does not show where the brushes are. I suspect they are under the panels just in front of the fan guard. They advertise "Brush holder design allows easy access to brushes", but I guess that is for the newer model which has a different panel with a black plastic cap where your picture shows a screwed on metal panel. That's where I would look first (after unplugging the grinder).
 
It does not look like the brush is worn very much. Did you check the other one?

It's hard to tell from the picture, but it looks like there is some rust colored powder on the brush and the brush holder. Maybe open up both sides and blow it out.
 
Aside from the rust, and blowing it out, the brushes look okay don't they? Plenty of brush left right?
 
It looks like they are plenty long. I assume the other side is similar and the springs are both good.

The inside of the controller looks good, there is no sign that a component burned out. I think it's probably 50/50 whether it is the motor or the controller and I can't think of any other simple things to test. Maybe there is a forum that specialized in electronics and/or motors where somebody might know what to do.
 
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