- Joined
- Sep 1, 2018
- Messages
- 672
No. Just saw video little while ago. Have a kb controller but that’s too easy. Not really. Too damn cold for me to mess with much.
The circuit is a pulse width modulator supplied with d.c. voltage by a bridge rectifier and capacitor filter. The PWM is switched with a MOSFET power transistor which is triggered via an optoisolator by a custom controller. I used a shop-built encoder to monitor motor speed and apply feedback when it sensed a motor slowdown or speed up. As mentioned above, I use an inrush current limiter to protect the diode bridge but bypass it with a time delay relay after about 1 second. This accomplishes two things. One, the motor can operate on full power after one second as opposed to slowly ramping up over a period of several minutes and two, if the power is switched off and immediately switched back, the inrush current limiter is cooled down and will function as intended. The control circuit consists of common discrete components operating in analog fashion. I chose this route rather than digital control via a microprocessor and software because I wanted components which would be available some twenty years from now.RJ what you have done sounds like what I need . A shop built PWM , how did you do it ?
No Load Spindle RPM | Torque, lb-ft. |
10 | .2 |
40 | 1.0 |
60 | 1.0 |
80 | 1.5 |
100 | 2.2 |
140 | 3.0 |
180 | 4.7 |
240 | 5.2 |