Author Topic: 134 MOB Resistors  (Read 3788 times)

todd432

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134 MOB Resistors
« on: March 06, 2015, 07:54:34 PM »
Hi

I have question about the resistors to cut the amp draw or match the amps of my steppers.

So I have 203v Geckos on an alum heat sink, 570 oz 5 amp nema 23 motors and 60v power supply ( little more than I need ).
According to Gecko...... 5A steppers needs  117.5K resistor per motor.
But..... I thought I'd try 4A resistors 62.67K per Gecko

When I tried the 4 amp resistors the motors could not, would not take full power. They would start to move and then stall and made a weird sound like they were jammed.
I changed to the 5A resistors and all is fine motors run at full power, low speed & high speed.

Do the steppers need 5A to run?
I also have a G540, 48v power supply with 570 oz steppers and they work on that system. The G540 is only 3.5A (no resistors)

Just seems strange it didn't work with the 4A resistors.

Todd




« Last Edit: March 06, 2015, 11:37:49 PM by todd432 »

Steve Stallings

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Re: 134 MOB Resistors
« Reply #1 on: March 06, 2015, 08:08:07 PM »
The result you describe does not sound right. You should get
normal motion at 4 amperes. I suggest that you verify that
your resistors are really the value that you think they are.
They should measure about 62K with a meter. It sounds
like you might have 6.2K resistors.
Steve Stallings
www.PMDX.com

todd432

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Re: 134 MOB Resistors
« Reply #2 on: March 06, 2015, 11:36:25 PM »
Steve your right, I ordered 62 ohm not 62K
I did check them before but never looked at the symbol on the meter.

I really don't understand the numbers, how they relate to current flow.
What numbers let more current flow and what numbers restrict current. And 1/4 watt 1/2 watt?
I just kinda monkey see monkey do on some things.

That makes me feel a little better thou, it was me and not the hardware.

THX
Todd