I need to add torque control to a motor controller that already has speed control through a tach feedback signal. My thought is to use voltage feedback from the anode of the SCR's and scale it to the same signal level as the tach feedback. The tach ranges from 0 to 360Hz and 0-33Vrms AC signal which is fed to a LM2907 in the following circuit with tach signal coming in on A8 and A9 (ignore the writing):
The SCR circuit:
So my question is: Do you think I can take the voltage from A4 in front of the load coil and use something like an LM331 along with some op amps to generate the appropriate range of signals to feed into the LM2907? Or will the pulsed form of the SCR voltage make it incompatible with VFC's like LM331?
If this won't work my other idea is to use a Hall effect sensor to get an analog voltage and then manipulate it to get the appropriate waveform to feed into the tach circuit.
Any thoughts or comments would be appreciated.
Thanks,
Shane
The SCR circuit:
So my question is: Do you think I can take the voltage from A4 in front of the load coil and use something like an LM331 along with some op amps to generate the appropriate range of signals to feed into the LM2907? Or will the pulsed form of the SCR voltage make it incompatible with VFC's like LM331?
If this won't work my other idea is to use a Hall effect sensor to get an analog voltage and then manipulate it to get the appropriate waveform to feed into the tach circuit.
Any thoughts or comments would be appreciated.
Thanks,
Shane