From another thread, I'm hearing that some drive manufacturers disable their brake choppers when the drive is not running, thus making the brake chopper/resistor ineffective in controlling the DC bus when the drive is idle.
I've never run into this. Would someone please fill me in on what...
Would one of you Siemens guys please advise me on a Model #6RA7091-6FV62-0-Z DC drive. Specifically, is it reversing? regenerative? Max hp, amps, or kw at 500V on armature?
Thanks in advance.
I can't seem to make the numbers come out converting the HP formula (ft-lb x rpm/5252) to KW (N-m x rpm/9549).
If I substitute .746kw for hp and N-m/.74 for ft-lb I get
.746kw = N-m/.74 x rpm/5252
Solving for kw I get N-m x rpm/2899
What am I doing wrong?
I have seen it claimed that induction motor overload capacity falls as the square of the overspeed while the motor continuous torque rating falls as an inverse of the overspeed. Using these rules, a motor with 200% overload capacity at base speed would have no overload capacity at double speed...
