- #1
RJK
- 6
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A while ago I built a pc board that serves as a 3 channel SS relay. The output thyristors are 25A. This circuit uses a zero cross opto coupler to fire the thyristor and turn it off (DigiKey MOC3042). I've used many of these to control aa AC wash machine motor (on/off). The first question is if I could substitute this thyristor (DigiKey Q4015L6) with a big monster one like a 520A RMS (DigiKey ST330S04P0-ND) ?
The second question has to do with controlling the PWM circuit. I think I need to reverse polorize the thyristor to shut it off. If so, then a second reverse polorized thyristor (across the motor)could have the inverted gate polarity with respect to the first thyristor. When the PWM signal drops out then Thyristor 2 reverse polorized thyristor 1 to shut it off and there is no current flow. Then when the PWM comes on thyristor 1 comes on again (T2 now off), and the motor has current. Is this possible to make work?
By the way, this is for my electric car, a 66 MGB.
Roger
The second question has to do with controlling the PWM circuit. I think I need to reverse polorize the thyristor to shut it off. If so, then a second reverse polorized thyristor (across the motor)could have the inverted gate polarity with respect to the first thyristor. When the PWM signal drops out then Thyristor 2 reverse polorized thyristor 1 to shut it off and there is no current flow. Then when the PWM comes on thyristor 1 comes on again (T2 now off), and the motor has current. Is this possible to make work?
By the way, this is for my electric car, a 66 MGB.
Roger