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Power Supply for stepper

B

ben

Jan 1, 1970
0
I have a golf cart charging transformer with two 45 V output coils. I
need 30 to 40 Volts DC at ~ 20A to run stepper motors. Can anyone help?
TIA, Ben
 
I

Ian Stirling

Jan 1, 1970
0
ben said:
I have a golf cart charging transformer with two 45 V output coils. I
need 30 to 40 Volts DC at ~ 20A to run stepper motors. Can anyone help?

Take one coil, attach a bridge rectifier, a capacitor, and run a buck
SMPS off it?
 
B

ben

Jan 1, 1970
0
Thank you for your prompt reply. However, since I am just an in-home
shop tinkerer, I did not understand "buck SMPS". After hours of
research I realize this is beyond my abilities to design with any
possibility of it working. If possible could you or someone supply a
schematic with component listing.
 
I

Ian Stirling

Jan 1, 1970
0
ben said:
Thank you for your prompt reply. However, since I am just an in-home
shop tinkerer, I did not understand "buck SMPS". After hours of
research I realize this is beyond my abilities to design with any
possibility of it working. If possible could you or someone supply a
schematic with component listing.

Alas, it's probably not really possible.
At this sort of power level (800W), there are a number of things in the
construction, heatsinking, ... that have to be just right.

Not to mention that if you don't understand what you're doing the
schematic needs to have all the 'obvious' things spelled out that may
not be normally present.

What sort of electronics projects hgave you done, htere may be other
ways.
 
C

Chris

Jan 1, 1970
0
ben said:
I have a golf cart charging transformer with two 45 V output coils. I
need 30 to 40 Volts DC at ~ 20A to run stepper motors. Can anyone help?
TIA, Ben

Hi, Ben. The easiest solution for a "tinkerer" would be to use a
rectifier and filter capacitor to get around 60VDC, then use a
resistive current limiter to keep the coil current to spec.

L-R drive has the advantage of getting somewhat more torque at higher
speeds, at the obvious cost of wasting a lot of power through heat.

See Jones on Steppers:

http://www.cs.uiowa.edu/~jones/step/

particularly Section 4: Current Limiting for more information on this
and other methods to accomplish what you want. See particularly Fig.
4.1a. -- suitable for lower speed operation.

If you're looking for an inexpensive source of surplus power resistors,
you could do worse than Surplus Sales of Nebraska.

http://www.surplussales.com

Be careful, and don't forget the diodes!

Good luck
Chris
 
Ian said:
Alas, it's probably not really possible.
At this sort of power level (800W), there are a number of things in the
construction, heatsinking, ... that have to be just right.

Not to mention that if you don't understand what you're doing the
schematic needs to have all the 'obvious' things spelled out that may
not be normally present.

What sort of electronics projects hgave you done, htere may be other
ways.

Ian,
How about a modest step-down transformer in front of the thing,
allowing a simple full-wave bridge + filter cap? Might there be a
suitable tapped transformer, such as for line voltage conditioning?

Regards,
James Arthur
 
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