Society of Robots - Robot Forum
Electronics => Electronics => Topic started by: Builder1 on November 26, 2008, 12:44:10 AM
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Hello Everyone,
I've bought two 24 Volt 375 Watts electric scooter motors made by Unite Motor to power my robot. The problem is I bought them from Ebay and the seller does not have the specs sheet for them. I've looked on Unite Motor's website and all over the net for the specs but didn't have much luck. So without a specs sheet how do I decide which motor controller I can use safely? How does one find out the max current any given motor will draw with load? Thank you in advance for your response.
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375W/(24V)~=15A, though the peak current during a stall/changing directions might be higher.
Guys, correct me if I'm off here, but I *think* you can get the stall current draw by measure the resistance of the coil. Since V=IR, I=V/R. Some preliminary tests with a small motor seems to support this hypothesis.
Or, if you have a beefy enough power supply and a meter that can handle high currents, you can lock down the shaft and see what current you draw, though I take no responsibility if something catches on fire or explodes :P
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A good rule of thumb is that the peak starting current is 6 times the full-load current.
You really don't need to concern yourself with this, though. A >= 15A motor drive will handle that motor (e.g. the Dimension Engineering Sabertooth 2X25).