DC drive w/AC motor?

anvilring

anvilring

Joined
Nov 29, 2000
Messages
2,869
Now I'm completely confused. After my earlier two posts about sorting out my DC motor and its drive, I happened to look at this old Bader III that I've been using all these (20!) years, and damned if it doesn't say that it has a DC drive! Is that right? That this is an AC motor correct?, and the drive is DC? So that drive(VFD?) is converting alternating current to a DC which in turn is powering my motor? I hate to keep asking redundant questions but I swear, I get confused about this. Here are some pics of my motor /controller tell me what's going on here electrically please.


Generated from my Samsung SM-G955U1 using tools.sportscard.trade


Generated from my Samsung SM-G955U1 using tools.sportscard.trade

Generated from my Samsung SM-G955U1 using tools.sportscard.trade
 
Here is a quick video of the motor doing virtually nothing! I just don't get this...

Watch "No power! DC knife grinder motor problems." on YouTube
 
Like Spalted said, the motor is a DC motor and it is a DC drive. Since you have a running drive and a running motor on your other grinder, you could test whether the motor or the drive is at fault on the grinder that does not have any power. I don't know if there is a potential to end up with two bad drives and/or two bad motors, so I don't necessarily want to recommend that.

I am a bit puzzled that the Baldor drive came with a 1.5HP motor and is running on 110V. I briefly looked at the manual for the Baldor drive and like the KB drive, it says you need 230V to drive a 1.5 HP motor with a 180V armature voltage. I guess you are running it on 110V and 90V armature voltage at reduced power. The manual for the MM23201 on the grinder that has issues has a warning not to do that to avoid damage to the transformer.

If you feel adventurous, you could hook up the motor that is stalling to the Baldor drive. You need to verify that all jumper settings on the drive are correct.
 
50451466528_854952f6ed_z.jpg

That's a DC Drive and that's a DC motor

The clue on the motor tag is the 180 Armature Volts
A rotor is the rotating part in AC motors, whilst an armature is the rotating part part in DC motors

DC motors are 90 or 180 V DC
AC motors that you want are 220-240 VAC 3 phase

This motor tag also lists the Brushes 2/BP5000T15 - AC motors have no brushes.


Do not mix and match the good controller and motor with the non running controller and motor to trouble shoot.
They are on different voltages.
One is 90, one is 180


At the time these were made dc was the way to go for variable speed.
Now AC VFD and 3 phase motor is the way to go.


Try and find a good motor repair shop to diagnose your DC motor and controller.


When I asked for photos of the insides of the broken DC controller, I didn't mean the wires
Show all the electronic bits close up, maybe we can see that a component is cooked-black, bulging, leaking.
If it's 20 years old, perhaps a capacitor is bad.
Stick your nose in there and see if you can nail down the location of a burned smell.


It doesn't pay to pay a shop rate for someone to fix a controller.
You can buy a new one cheaper.

If you do go new, get a KBAC27D and a matching 1.5hp 3 phase motor. 56c frame
 
12345677910 ....
Much thanks! That explains a lot right there. So, let me ask you this:; if it were up to you to buy a new controller for my ailing one horsepower motor in the original post several back, which one would you get? DC controller for that one horse motor? I wouldn't mind spending $150 bucks to see if that would fix the problems I have with the little Lesson motor. I don't know what my chances are, but $150 bucks is a lot cheaper than $700 bucks. I can afford either one, truth is I just want a damn grinder that works!
 
Also, thanks to everyone else who's replied to my posts (of which there are three now ... ). Sorry for the repetition, but I am having a hard time coming to an understanding with electricity these days!
 
12345678910 said:
Do not mix and match the good controller and motor with the non running controller and motor to trouble shoot.
They are on different voltages.
One is 90, one is 180
Click to expand...
I generally agree with that in the sense that there is a risk of damaging a working component. However, either one of his drives can be configured to run a 90V or a 180V motor.

I looked at the photos in the other threads and there are no blown or bulging caps and no sign of anything burnt. I found the manual for the (possibly) bad drive and it is a NEMA 1 enclosure, which leads me to believe that it is more likely that the drive is bad, not the motor.

A KB NEMA 4 DC drive is just under $200 shipped to your door, the Baldor about $330. A replacement 1 HP DC motor is about $230.

The equivalent AC replacement option is about $400 (KBAC-24D + 1HP motor), a bit more if you want to add a reverse switch.

The upgrade AC option is about $550 (KBAC-27D + 1.5-2HP motor).

I would spend an extra few bucks to get the proper cable glands, relatively cheap at McMaster.

So, you can save about $200 if you can figure out whether the drive or the motor is bad. If you don't have a motor repair place and no testing equipment, the only option to figure that out is to risk frying the controller on your Bader III... I would not recommend that. Personally, I would probably do it after making sure the Baldor drive is properly configured for the 90V motor.

The grinder looks well built, I think it is worth putting $400 into.
 
anvilring said:
Also, thanks to everyone else who's replied to my posts (of which there are three now ... ). Sorry for the repetition, but I am having a hard time coming to an understanding with electricity these days!
Click to expand...
With all the recent bashing of necroposting, I can see how one would want to start a new thread after a few days!:D
 
anvilring said:
12345677910 ....

Much thanks! That explains a lot right there. So, let me ask you this:; if it were up to you to buy a new controller for my ailing one horsepower motor in the original post several back, which one would you get? DC controller for that one horse motor?

I wouldn't mind spending $150 bucks to see if that would fix the problems I have with the little Lesson motor.

I don't know what my chances are, but $150 bucks is a lot cheaper than $700 bucks. I can afford either one, truth is I just want a damn grinder that works!
Click to expand...

Ask Hubert which drive and where he saw this one
"A KB NEMA 4 DC drive is just under $200 shipped to your door"
the prices I see on KB are higher

I like KB electronics.
USA made, Real in USA tech service, they anwser the 1-800 phone and they speak english.
NEMA 4
90 VDC
110-120 VAC input
1 HP


https://www.kb-controls.com/product.sc?productId=112&categoryId=4

https://www.kb-controls.com/product.sc?productId=13&categoryId=4

Try finding a local motor shop taking in the whole grinder and getting some diagnosis, motor vs controller.
 
12345678910 said:
Ask Hubert which drive and where he saw this one
"A KB NEMA 4 DC drive is just under $200 shipped to your door"
the prices I see on KB are higher

I like KB electronics.
USA made, Real in USA tech service, they anwser the 1-800 phone and they speak english.
NEMA 4
90 VDC
110-120 VAC input
1 HP


https://www.kb-controls.com/product.sc?productId=112&categoryId=4

https://www.kb-controls.com/product.sc?productId=13&categoryId=4

Try finding a local motor shop taking in the whole grinder and getting some diagnosis, motor vs controller.
Click to expand...
The second one you linked (KBPC-240D) is available on amazon for $195.30 with free prime shipping. Maybe you are looking at Canadian prices, the second link you posted shows the same price ($195.30) on the KB website for me but I don't know about shipping. I assume it is suitable from the brief description, but I would give them a call. They have great tech support.
 
Anvilring, I have watched these two threads and have cone to one conclusion ... You need a friend or a professional who knows electrical motors and controllers. Not being able to read the plate or understand the operation of the drive could cause a serious problem.
 
Anvilring, the pictures you posted of the motor brushes don't show what's important...the faces that wear against the armature.
I have the same machine you have there and while mine never slowed down like yours occasionally the motor would want to jog rather than keep a steady speed.
the faces of your brushes could very well be wearing or collecting junk on them affecting the way it runs.
what I do is pull the brushes, put it on a disc grinder, and while holding back the spring from the brush
to keep it flat, just touch it lightly to the grinder to flatten the faces. it's important to just go VERY lightly and keep it square.
doing this occasionally to my motor keeps it running like brand new.
 
bladegrinder said:
Anvilring, the pictures you posted of the motor brushes don't show what's important...the faces that wear against the armature.
I have the same machine you have there and while mine never slowed down like yours occasionally the motor would want to jog rather than keep a steady speed.
the faces of your brushes could very well be wearing or collecting junk on them affecting the way it runs.
what I do is pull the brushes, put it on a disc grinder, and while holding back the spring from the brush
to keep it flat, just touch it lightly to the grinder to flatten the faces. it's important to just go VERY lightly and keep it square.
doing this occasionally to my motor keeps it running like brand new.
Click to expand...

Hmmm.... my brushes are sort'a "C" shaped on their ends from touching the commutator ( I suppose). So they are supposed to be flat on the end? ideally? I did not know that.

Stacy, I'll be ok... I won't burn anything down fixing this. My thought now is to get the higher end drive so that "if" it is the motor, I can use the good 1.5hp DC motor I've got at the shop w/a bored out drive wheel to 7/8th".
 
Yes, when you buy new brushes they have flat faces and wear to the armature.
I highly recommend you try what I do. I've been doing it to the motor on my machine at least once a year for over twenty years....the same brushes that came with it.
just remember, they have the hardness of pencil lead so you just touch them to the sander to get the faces flat.
 
anvilring said:
Stacy, I'll be ok... I won't burn anything down fixing this. My thought now is to get the higher end drive so that "if" it is the motor, I can use the good 1.5hp DC motor I've got at the shop w/a bored out drive wheel to 7/8th".
Click to expand...
Double-check that whatever drive you buy can run a 1.5 HP/180 V motor on 110V if that's all you got.
 
I hate to admit this, but I moved a bunch of stuff that hasn't been moved in probably a decade from out under my grinding bench and behold, my Bader III is running on 220 volt! Not only that but as I pulled more stuff out along that side of the shop, there's another 220 v plug in line with it
So now, can I proceed as planned? And get the KBor Baldor controller that will handle either 90 or 180 v, then first see if it fixes my 90-volt motor DC motor, and if not I'll hook up my new 1.5hp DC to it and all is well.
The Baldor controller which is exactly the one that I have on the Bader machine:
https://motorsandcontrol.com/baldor...CizgMEr83nM9zS03TZQlrIZf0d6XqqxhoCotQQAvD_BwE

or the KBAC27D

Now the question is, could I run both of these machines at the same time? That is if I power them both with 220 volts? normally when I'm working by myself I'm using one of the other, but sometimes there's more than one person in my shop!
 
That's good news.

The KBAC27D is not what you want. It is a VFD, not a DC drive. There are a couple of KB DC drives linked in post #10 above.

You should be fine running both grinders. Take a look at the breaker to see what you've got.
 
I think the Baldor drive may be a rebranded KB drive KBPC-240D. At least that number appears in the documentation link on the Baldor site. The KBPC-240D is much cheaper on Amazon.
 
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