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Ratings:
1/8 to 3 HP at 200-240 VAC 1-Ph.
1/8 to 5 HP at 200-240 VAC 3-Ph.
1/2 to 7.5 HP (ND) at 380-480 VAC 3-Ph.
• Overload Capacity:
150% for 60 sec. (Heavy Duty)
120% for 60 sec. (Normal Duty)
• Control Methods: V/f Control
• DC injection braking, ramp to stop
• Electronic reversing
• Adjustable accel/decel: 0.0 to 6000.0 seconds
• Controlled speed range: 40:1
• Speed Regulation: ± 0.5 to 1% with slip compensation
• Displacement power factor: 0.98
• Output frequency: 0 to 400 Hz
All VFD applications require programming. You have to make it do what you want. Parameters like minimum and maximum frequencies, number of motor poles, maximum current, overload response, braking behavior, acceleration profiles, etc. must be set by the user to match your installation's needs. The voltage/frequency curve is user configurable too, which is very useful for your kind of application where you are operating outside the normal frequency range of the motor. Good VFDs come with a display that can be set to show the motor speed (or any number of other parameters). If I were doing this, I would use a 1HP 208V two-pole motor and a 1HP VFD with a 240V input.
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 variable frequency drive is becoming popular in setting up 3phase powered equipment. Most of the units are capable of producing variable frequency 3 phase power from a single phase source. The downside being there is a reduction of power rating. In other words, you would need a 5-6HP VFD to run a 3HP motor if the input is single phase. Now the beauty of using a VFD inverter is your ability to control motor speed. You can crank the cycles down so that the motor is barely turning. or if you needed more speed, that is possible as well. Maybe even to the point of speeds that are dangerous. For instance, running a 60hertz motor at 400hertz.
