Guys,
I'm not that experienced in driving large DC motors. At work my project is to monitor the current drawn by a variable speed DC motor. The motor is a 141V DC motor from Panasonic. It has on-board power electronics so you can control the speed with a 0-5V signal. I'm using a 1000uF filter capacitor across it to stabilize the voltage. The motor draws about 1A when running.
I'm measuring the current across a shunt resistor on the low side, using a TI INA-195 shunt amplifier to get a nice voltage out of the mV range. This chip seems to work fine, but it looks like I've blown up a couple of them in one experiement where I was turning the motor on and off about every 60s. Could I be getting a voltage spike when turning off the motor? Should I add a diode across the motor to protect from back/emf voltage spikes? If yes, what kind of diode should I use?
Thanks for any help.
I'm not that experienced in driving large DC motors. At work my project is to monitor the current drawn by a variable speed DC motor. The motor is a 141V DC motor from Panasonic. It has on-board power electronics so you can control the speed with a 0-5V signal. I'm using a 1000uF filter capacitor across it to stabilize the voltage. The motor draws about 1A when running.
I'm measuring the current across a shunt resistor on the low side, using a TI INA-195 shunt amplifier to get a nice voltage out of the mV range. This chip seems to work fine, but it looks like I've blown up a couple of them in one experiement where I was turning the motor on and off about every 60s. Could I be getting a voltage spike when turning off the motor? Should I add a diode across the motor to protect from back/emf voltage spikes? If yes, what kind of diode should I use?
Thanks for any help.