What Voltage are my Servo's?

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08-21-2009, 10:53 PM
austin.mn

What Voltage are my Servo's?

Last winter I picked up some large servos and a set of Rutex R2020 drives for my old Bridgeport Boss machine. I had intended on getting them onto the mill right away, then got busy with work and so that project went on the back burner. Anywho, The motors in question are big. They are Japan Servo DLs140s1-01, the label also states voltage constant of 13.9mV/RPM. It was my understanding that DC servos should be run to about 3500 rpm max, with that I am under the impression that I should be pushing a little over 48 volts into them. Let me know if that sounds about right to anyone else. Now I also need to figure out how much current these should consume. If anyone has any idea how I can go about figuring that out please let me know. The mounting flange on these is about 5.5 inches square and the body is that same diameter, so these are pretty fat motors. They came off of an older robot arm.

Thank you in advance.
09-19-2009, 04:19 PM
Larken

That may be the label for the tach you are reading. It could be 13 volts/1000 rpm, but even that is a bit low for a big motor.

Best to just put the 48 volts directly to the motor and see if it moved your machine fast enough.
09-19-2009, 04:45 PM
Al_The_Man

If you feed them off a 12v automotive battery and get around 800 rpm, they will be around 14v/1000rpm (13.9mV/rpm).
If you do not have the torque constant value, you could make an educated guess from comparable motor sizes from other manuf, then using a moment arm off the shaft and a spring scale on the other end, slowly increase the armature current until the estimated constant Torque value is achieved (Nm or In-lbs) and measure the current at this value.
Al.
09-19-2009, 05:22 PM
Larken

My eyes are getting bad, i thought it said 13.7mv/1000 rpm.
09-19-2009, 11:21 PM
austin.mn

Quote:

Originally Posted by Al_The_Man

If you feed them off a 12v automotive battery and get around 800 rpm, they will be around 14v/1000rpm (13.9mV/rpm).
If you do not have the torque constant value, you could make an educated guess from comparable motor sizes from other manuf, then using a moment arm off the shaft and a spring scale on the other end, slowly increase the armature current until the estimated constant Torque value is achieved (Nm or In-lbs) and measure the current at this value.
Al.

Thanks Al, I will give that a shot. They seem like they should be plenty big enough to move the machine around. I just don't want to cook them as I only have one spare motor.