I have a 460v 3 ph. 3 hp. Allen Bradley VFD. I would like to apply DC to the buss from a single phase power supply instead of a rotary converter. Any problems with this?
- posted
16 years ago
Allen Bradley 1305 VFD
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- posted
16 years ago
Most of these smaller VFDs will run off DC. The problem is you need to supply 680 V DC to it. It may be a lot easier to supply it with single-phase 480 V by using a step-down transformer backwards, and using the internal rectifier, etc. Unless you will run the motor at full rated load for extended periods, it will probably work fine. I have a 1 Hp 230 V VFD on my Bridgeport mill with 1 Hp motor. The VFD is rated for 3-phase input only, but it has run fine for years.
Jon
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- posted
16 years ago
Maybe you can run the DC bus from an external source, but the control electronics do not run from the DC bus, they need the AC input to some transformer for (possibly?) 5 volts, and whatever other voltages are used to for the logic, and transistor drives.
IOW, I think you ~might~ be able to give it the high voltage 680 volts DC power, but you might also have to give it the 480 volts AC to drive the computer and transistor drive/control circuitry.
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- posted
16 years ago
Nope, most of the smaller VFDs use a little DC-DC power supply that runs off the main rectifier. You can usually tell these because, when idling and you cut off the mains supply, they continue to "run", ie. the panel display stays active for many seconds, then you get an undervoltage display, then it finally powers down some 15+ seconds after power is removed.
Jon