220V Ez Clutch Motor Woes- Troubleshooting Help?

[gottaknow]

Just curious, why not just use the correct motors to start with? You lose substantial torque single phasing a 220 motor.

Regards, Eric

[GerryR]

I believe the OP bought a machine with the 3 ph motor on it. It may be less expensive to just replace it with the "correct" motor, but these are just some options if he wants to keep everything "original."

With the VFD, you don't lose any torque, as it generates 3 ph out from the 1 ph in. Also, if the motor can take it, from the rated RPM on down, it can be set to run in constant-torque mode, so you get good torque at low RPM's. If you want to run above the rated RPM's, it will then run in constant-horsepower mode, and the torque drops off accordingly. But it gives a lot of options, not the least of which is variable speed. The phase converters (not the rotary converters, which generate all 3 phases) just start the motor, and then the motor runs single phase at 2/3 the rated power.

[gottaknow]

Heh...so adding a VFD keeps it original? . Forgive me, it's Monday.

Regards, Eric

[GerryR]

You're forgiven, but yes, mechanically speaking.

[eglideride]

GerryR is correct- the VFD is the easiest - cheaper and safer solution....if this were a plumbing project, all you risk is getting wet.

Electricity can kill and or cause fires,,,find a qualified electrician to help you with the VFD. Not worth losing your shop/house- your life or someone elses, over.

[electrathon]

Electricity can kill

Water kills far more people than electricity. Rather than messing with a VFD, why not install a servo motor? About the same price and many people with clutch motors are going that way anyways.

[Northmount]

Most new sewing machine users have trouble with controlling speed on a clutch motor, so yes, a servo, and for their cost is the way to go. A VFD on a clutch motor does give you a range of speed control, but not nearly as convenient as a servo with speed control from the pedal. A VFD on an induction motor losses a lot of torque at low speeds, and tends to increase the running temperature of the motor. It's not a fix all!

If you need low speed torque, get a servo with internal 3:1 gear reduction. You'll be much happier than with a clutch motor on a VFD for similar amount of money, or less. Toledo Industrial has servo with gear reduction.

Tom

[GerryR]

The VFD can operate in "constant torque " mode if the motor is designed for VFD operation (because of both voltage and current (heating) requirements needed to accomplish this). However, you can set the VFD to run with a standard 3 ph motor, and you can set it to run just like a DC "servo" with an external (foot) speed control. I have a 1 hp, 3 ph, 230 VAC, 1725 rpm motor to which I added a 5:1 gear reducer, and then did a further reduction through the pulley, giving about a 7:1 total reduction. I made a foot control (could have bought one, but had what I needed to make one) and can vary the speed from 0 to about 240 strokes per minute (which totally suits my needs). With the reduction, the motor is at ample speed at low strokes per minute to prevent any over-heating and there is ample torque to sew 3/8 leather. If by chance I need to go faster, I can reset the upper frequency limit in the VFD and drive the motor in "constant hp" mode (lose some torque) and move along, for example on thinner, garment material.

My point is that the VFD is as versatile as a DC drive if set up properly. I am not that familiar with the so-called DC servo's sold for sewing machines, but unless there is some sort of feedback from an encoder (which I tend to doubt because of their low cost), it is not a true "servo" but merely a "variable speed" DC drive. So again, the VFD, I believe, is a viable option, especially if you already have the motor, which the OP does have. The DC servos that boast needle position capability, I assume, do have some form of positional feedback encoder or sensors, and would be more inline with a true "servo" system.