Needing some help up here in Alaska to hook up motor to wheat grinder.
Have a small 130V DC Bodine Gear Drive motor. Model 192. Only pulls .3 Amps, for a wattage of 39.
Need to put a rectifier, capacitor and in-line fuse in place to convert the AC to operate this DC motor. Have read some posts, but not clear enough for me to understand.
I know a person can buy an off-the-shelf controller for about $100. But I am hoping I can just add these parts to get it to run (for about $10-$15).
Problem is I am not sure of the exact parts needed.
Rectifier I need (a 130V .3A) is not anywhere to be found.
Bridge rectifier - Our small RS has a bunch of rectifiers/bridge rectifiers, and most appear to be “over-rated” ex: 200V 25A, 200V 50A, 600V 25A. Is it OK to use one of these as it is “over-built”?
For the capacitor, are their different types? A 10uf be OK?
For fuses, most at RS seem to be 50 Volts rated…OK to use an in-line fuse with 200V and 1 amp?
I can build a house, but electronics is greek to me...
Thx a bunch

 

The only safe way to do it is with a TRANSFORMER, Rectifer, Capacitor...
I predict imminent thread closure.

 

Just use a 25amp rectifier. No capacitor needed.

1 amp 200v fuse in line side should be fine.

 

You could use a bridge rectifier if you know how it hooks up. Bigger voltage and amps the better.

A 1 amp 150 volt fuse would probably work OK.

 

Bridge rectifier - Our small RS has a bunch of rectifiers/bridge rectifiers, and most appear to be “over-rated” ex: 200V 25A, 200V 50A, 600V 25A. Is it OK to use one of these as it is “over-built”?

It is absolutely OK to use an "over-rated" rectifier. Problem: Fully rectified AC is ~170V DC. This might be OK for your motor, or it might not. I'd be a bit nervous. And if you want control you'll need something more anyway.

 

A ghetto solution would be to place a light bulb in series with your motor. On paper a low wattage bulb (12W) would drop the voltage from 170 to 130. You could experiment with bulbs from 7-20W or so, and see what happens at the motor.

I'd use a capacitor filter as well. I haven't done the math, but I think you'd want at least 1000µF electrolytic in parallel with the rectifier DC poles, with a voltage rating of 200V or more.

 

RS should have 1N4007 rectifiers good up to 1000 volts. I'd use a fuse and a switch to be safe too!

 

I'd use one of the pre-built bridges. Just easier, IMHO.

 

No problem with peak voltage, just don't use capacitor.

 

They are premade: http://www.radioshack.com/product/i...gclid=CNja4r3OkL0CFeRlOgodbVQA-Q&gclsrc=aw.ds

25 pack of pot luck diodes: http://www.radioshack.com/product/index.jsp?productId=2062589

MAY include 1N4007...

 

... just don't use capacitor.

Why not? It'll reduce the ripple.

 

Full wave rectifier only is fine, this is no different than running a SCR drive, you will only get 90v on 120vac but usually it runs those Bodine motors fine.
Max.

 

...you will only get 90v on 120vac...

You guys are confusing me. (It's not hard to do!) I can accept that you don't need the filter cap, but how do you get 90V DC from rectified 120V AC?

 

RMS voltage is about 2/3

 

Not a resistive load.
Just as a capacitor input filter increases the voltage above rms. A choke input reduces voltage below rms.

That's my understanding. I didn't look it up.

 

If you were to check out the Terms of Service found at the bottom of the page you will find that there are restrictions on discussion of certain topics. Transformer-less power supplies is one such topic.

6. Restricted topics. The following topics are regularly raised however are considered "off-topic" at all times and will result in your thread being closed without question:

• Any kind of over-unity devices and systems
• Automotive modifications
• Devices designed to electrocute or shock another person
• LEDs to mains
• Phone jammers
• Rail guns and high-energy projectile devices
• Transformer-less power supplies

In order to continue with this discussion a AC mains transformer would have to be incorporated into your design.

 

I've no dog in this fight.

Technically you may be totally correct.

In my opinion, a dc motor connected thru rectifier only, with no other components, could easily be thought of the same as any other "how do I connect this motor" question.

It may be a good place to draw a line in the sand.

If not, backing up one step, and explaining a proper dc motor connection method, with an isolation transformer, is fine with me.

 

Se3ing that this thread is still open I will close it. It is indeed a violation of ToS.