Electric Motor question

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earlgo
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Electric Motor question

Post by earlgo »

Being a confirmed EI, I have a question for you whiz kids.
I have a 1/4 hp 115V DC Motor and I'd like to use it, but with the proper "stuff" to make it variable speed.
DC motor plate
DC motor plate

1) What do I need and where do I get it?
2) Would it be better to trash this and get an AC motor with a VFD?
This would be used to drive a very fine wire brush used for 'carding' rust blueing, so it does not need to be very powerful.
--earlgo (Electrical Incompetant)
Before you do anything, you must do something else first. - Washington's principle.
Bob D.
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Re: Electric Motor question

Post by Bob D. »

Leeson, Bodine, KB, all make controllers for these motors. Look on Fleabay, should be pretty reasonable.

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RichD
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Re: Electric Motor question

Post by RichD »

Minaric and Dart are two more excellent brands, I use these.
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rrnut-2
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Re: Electric Motor question

Post by rrnut-2 »

2 wires or are there 4 wires coming out of it? 4 wires means that it has a field, so you want a dc controller that will support a field. There are a lot of the newer ones that won't. They will only run a permanent magnet motor. Of course that is ok if you have only 2 wires coming out of the motor.

Jim B
earlgo
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Re: Electric Motor question

Post by earlgo »

The motor has brushes and there are 6 wires coming out.

I said I was an EI but that wasn't enough of a clue for anyone to pick up on. Giving me brand names for thingys is like having someone ask for help with transportation for around town and the answer being Ford, Chevy or Honda.
What do I need?
--earlgo (Electrical Incompetant)
Before you do anything, you must do something else first. - Washington's principle.
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SteveHGraham
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Re: Electric Motor question

Post by SteveHGraham »

Sorry to hear about your ED (Electrical Dysfunction).
Every hard-fried egg began life sunny-side up.
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Bill Shields
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Re: Electric Motor question

Post by Bill Shields »

AC with VFD can solve many problems EXCEPT good torque at very low speeds....which is why as lot of DC motors are in service.

Most AC (3 phase) motors NOT SPECIFICALLY DESIGNED to be run at very low speeds on a VFD can have problems with ET (Extreme Temperatures)

VFD / AC are not MW



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10KPete
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Re: Electric Motor question

Post by 10KPete »

If the motor has brushes, you can run it through a light dimmer. A 1/4 hp motor will run on a light dimmer easily. I have a few set up that way. Cheap and easy.

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earlgo
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Re: Electric Motor question

Post by earlgo »

I asked my friend the exact same question and provided the same information to him about the 110V DC motor.
He took the time to explain exactly what I needed and how to check the motor leads.
I need a Full wave rectifier 300VPPV 5 amp capacity and a dimmer switch with 300W capacity or a AC 110V Rotary Knob Voltage Speed Controller DC Motor Variable DC 0-90V. All are available on E-bay for less than $35 total.
He also explained how the bridge rectifier modified the Sinusoidal AC into a Cycloidal wave and how the dimmer switch chopped the AC into pulses.
But thanks anyway to you fellows for the helpful suggestions especially about the possible use of the dimmer switch for a speed control.
--earlgo
Before you do anything, you must do something else first. - Washington's principle.
earlgo
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Re: Electric Motor question

Post by earlgo »

I bought the AC 110V Rotary Knob Speed controller 0-90V DC. My friend figured out the motor windings and put it all together. It works better than I had hoped and now I have a variable speed carding wheel for my experiment in rust blueing.
--earlgo
Before you do anything, you must do something else first. - Washington's principle.
earlgo
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Re: Electric Motor question

Post by earlgo »

In the interest of closure, this is what I ended up with in regard to the variable speed DC motor and controller.
It isn't pretty but it works.
DC motor and Samgold controller
DC motor and Samgold controller
--earlgo
Before you do anything, you must do something else first. - Washington's principle.
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neanderman
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Re: Electric Motor question

Post by neanderman »

earlgo wrote: Thu Nov 01, 2018 9:16 amHe also explained how the bridge rectifier modified the Sinusoidal AC into a Cycloidal wave...
Invaluable info! I'm not very good with electronics, but how to design a 'basic' DC power supply is something I do know. And it has served me very well over the years. Did he recommend a filter capacitor across the DC side of the rectifier? I've found that, even with motors, it can make a real difference in smoothing the DC output.
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