Electric Power Tools
Description
The major source of problems in the real world is conducted emissions and these are typically in the region of 20kHz to 10MHz. The source of the emissions is the output of the VFD which comprises 6 solid state switches that switch each output between the DC bus rails. These switches are typically high speed IGBTs which can switch in less than 100nS.
1hp VFD blows one of the fuses on the line side of the drive and then continues to operate on single phase supply. The fuse size that keeps blowing is a 6A fuse. This motor is a 9-lead motor which originally was wired incorrectly, which we thought was the problem, however now we have confirmed that the motor is wired correctly and it is still blowing this same phase fuse every time. I wouldn’t suspect the fuses are too small because after the fuse blows and the drive is running on single phase supply we would expect the current on the two remaining phases to increase and thus blow the other two fuses if they were marginal.
The challenge of this custom variable frequency drive design was to maintain constant airflow by changing motor speed as the filter changed from “no load” to “100% load”. The custom VFD design had to fit into an existing control panel with a height limitation of less than 2.5 inches. Fast start-up (<5 seconds) and intelligent set point return are some of the programmed features of this unique custom VFD design.
The idler motor starts and comes to speed immediately. The only three-phase I have on line is the 1hp Bridgeport and it starts right up also. I probably should not have buried my question in the middle of the post because I was just commenting about the amp draw. The question was: What does it cost to run the converter? Should I turn it off if I& acute;m not going to be running the Bridgeport for a while or just let it run? I do like the color emphasis ability of this software.
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VFDS LLC
2HP VFD, 5HP VFD, variable frequency drive, 7.5HP VFD
Address: 8235 W. Sunset Boulevard,
Los angeles, California
United States, 90001
Tel: +1-310-6421125
Fax: +1-310-6421375