I want to build an H-bridge driver for a 90 VDC motor, just like this one.
I've designed a (possibly quite clumsy) circuit in LTSpice for this effect, based on a previous design that @ronv was kind enough to help me with. This circuit will not be driven from mains, but rather from a 1:1 isolation transformer working at 120VAC/60Hz, so it should comply with the TOS.
The circuit is running at 1.25 kHz, and only M1 and M4 are being driven in the sim. M4 is doing the switching, since I'm under the impression that nFets are better suited than pFets for this purpose.
Questions:
I've designed a (possibly quite clumsy) circuit in LTSpice for this effect, based on a previous design that @ronv was kind enough to help me with. This circuit will not be driven from mains, but rather from a 1:1 isolation transformer working at 120VAC/60Hz, so it should comply with the TOS.
The circuit is running at 1.25 kHz, and only M1 and M4 are being driven in the sim. M4 is doing the switching, since I'm under the impression that nFets are better suited than pFets for this purpose.
Questions:
- Is it normal that the rectified voltage accross the motor's coil never reaches zero?
- Is my design more or less passable, or are there important changes/improvements that should be made?
- @MaxHeadRoom, you may be able to help me determine the correct coil resistance for the motor (since I don't have it with me at this moment) and perhaps even its inductance. Maybe you know ballpark figures for these values?
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