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BrianG · 09.30.2006, 03:37 PM

Sorry. I do get carried away. :dft001:

I guess my point is that it's not as easy as simply measuring the resistance and be able to figure out the current draw, especially since BL is three phase. If you had a capable meter, you could measure the current on one of the windings while running. But you'd have to have a meter capable of measuring fairly high frequency since the pulses are in the kHz. Most meters assume 60Hz as the frequency which changes things. Some are "true RMS", but you don't want that either since the signals going to the motor are square wave.

Much easier to measure the current and voltage on the battery pack. Even that changes depending on the load (take-off/acceleration vs maintaining speed). That's where the eagletree device comes in handy. It samples the voltage and current periodically to get a waveform.

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BrianG RC-Monster Admin Offline Posts: 14,609 Join Date: Nov 2005 Location: Des Moines, IA	09.30.2006, 03:37 PM Sorry. I do get carried away. :dft001: I guess my point is that it's not as easy as simply measuring the resistance and be able to figure out the current draw, especially since BL is three phase. If you had a capable meter, you could measure the current on one of the windings while running. But you'd have to have a meter capable of measuring fairly high frequency since the pulses are in the kHz. Most meters assume 60Hz as the frequency which changes things. Some are "true RMS", but you don't want that either since the signals going to the motor are square wave. Much easier to measure the current and voltage on the battery pack. Even that changes depending on the load (take-off/acceleration vs maintaining speed). That's where the eagletree device comes in handy. It samples the voltage and current periodically to get a waveform.