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Old 03-13-2013, 05:07 PM   #1
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Electric motor crossover.


Hello, I have a Kuenle 3hp, 3 phase electric motor that I want to switch for a single phase 3 hp electric motor that is more common here in the usa. Can anyone help me?

3-ph-mot. Nr. 3287 156109 10
Typ KMER 90 S 2
KW 1'5
V 230/460
A 5,6/2,8
RPM 3410
Iso B IP 54
VDE0530
DR/Y
cos 0,85
Hz 60

Thanks, Chris

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Old 03-13-2013, 06:14 PM   #2
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Electric motor crossover.


It may be cheaper and more useful to get a VFD that can run this motor with a single phase input.

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Old 03-13-2013, 07:55 PM   #3
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Electric motor crossover.


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Originally Posted by mpoulton View Post
It may be cheaper and more useful to get a VFD that can run this motor with a single phase input.
Even though I'm not a fan of VFDs, in this case I agree.

No frame size is listed, so it's very likely not a standard size. This could make replacing it very difficult. The shaft is probably not a standard size, so you'd need to either get a new sheave (if it's belt drive) or have the existing one machined to fit a standard shaft.

Also, you'd need to drill new mounting holes, and maybe tap them.

If you use a VFD, make sure that the only thing that's connected to its output is the motor. Nothing else. And make sure that the motor is connected directly to the VFD, no switches or disconnects between the VFD and motor.

Rob
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Old 03-13-2013, 08:01 PM   #4
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Electric motor crossover.


http://www.joliettech.com/what_is_a_...ency_drive.htm
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Old 03-13-2013, 08:23 PM   #5
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Electric motor crossover.


What voltage are u running at?
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Old 04-13-2013, 07:23 PM   #6
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Electric motor crossover.


Sorry for not responding sooner. I was out of the country and without internet service. This is a 220 volt motor (3 hp).

I also have a 1 1/2 hp 3 phase sander that I would like to hook up. Is a VFD the same as a static converter?

What size would I need to run both machines?

Am I understanding that the two machines must be hard wire and not set up with plugs and receptical?

What would be a good brand name VFD & what would I expect to pay for it?

Would it be easy for me to wire the VFD or would I have to hire a commercial electrician to wire it?

Thanks for the help and I will be standing by to answer any follow up question. Cn
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Old 04-13-2013, 11:29 PM   #7
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Electric motor crossover.


A VFD will run only one motor at a time. If it is to run two motors that are not the same, it'll need to be reprogrammed each time it runs the other motor. Some VFDs have the capability to run motor A then switch to motor B without reprogramming. The GE AF600 is such a VFD.

I don't know about price though, I just install and program VFDs, not buy them.

A static phase converter will operate a 3 motor on single phase power, but only at about 1/2 to 2/3 of its HP. A rotary phase converter will operate a 3 motor on single phase power at about 80 - 90% of its HP. A VFD will run it at very nearly full HP.

One thing about VFDs and more than one motor; never ever disconnect the motor from the VFD while it is running. To do so will blow out the output transistors.

Rob
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Old 04-13-2013, 11:43 PM   #8
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Electric motor crossover.


Quote:
Originally Posted by micromind View Post
A VFD will run only one motor at a time. If it is to run two motors that are not the same, it'll need to be reprogrammed each time it runs the other motor. Some VFDs have the capability to run motor A then switch to motor B without reprogramming. The GE AF600 is such a VFD.

I don't know about price though, I just install and program VFDs, not buy them.

A static phase converter will operate a 3 motor on single phase power, but only at about 1/2 to 2/3 of its HP. A rotary phase converter will operate a 3 motor on single phase power at about 80 - 90% of its HP. A VFD will run it at very nearly full HP.

One thing about VFDs and more than one motor; never ever disconnect the motor from the VFD while it is running. To do so will blow out the output transistors.

Rob
Those must be some pretty cheap VFD's.

The ones I use are not bothered by the load being disconnected....or a power failure....have torque limiting...fly catching....etc...
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Old 04-14-2013, 12:33 AM   #9
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Electric motor crossover.


Here's one:
http://driveswarehouse.com/p-2692-nes1-022sb.aspx

I have used Hitachi drives for a few 1ph->3ph applications and they seem to do just fine, at about the lowest available price. This new series is supposedly better than the L series I have. You could run both motors from this VFD (separately) but not with optimal programming since they have different operating parameters. I'd just get a separate drive for each. Here's a 2HP version for the sander:
http://driveswarehouse.com/p-2689-nes1-015sb.aspx

They are easy to wire, but hard to program. The programming manual that comes with it is a couple hundred pages, and the "quick reference guide" is a few dozen pages and doesn't cover everything you need to know. The programming interface is NOT user friendly at all, and the meaning of the parameters is not well explained in the documentation. They assume you already know about engineering drive systems and the control parameters for them. Once you get a handle on that, you'll be hooked on the amazing flexibility you get with a VFD on your machines, and you'll start adding them to everything...
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Old 04-14-2013, 10:21 AM   #10
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Electric motor crossover.


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Even though I'm not a fan of VFDs, in this case I agree. Rob
Rob. I have heard you say this multiple times. Why don't you like VFD's?
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Old 04-14-2013, 12:07 PM   #11
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Electric motor crossover.


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Rob. I have heard you say this multiple times. Why don't you like VFD's?
Several reasons;

1) They cause harmonic distortion in the incoming power source. This is rough on motors and transformers. The waveform just about anywhere (VFDs present or not) is getting more distorted as more VFDs are installed. Nationwide.

2) They're rough on motors. Unless the motor is wound with spike-resistant wire, a VFD will wreck a motor, worse if there's any distance between the VFD and the motor. Reflected power causes voltage spikes that jump between individual wires in a winding. This can be solved by the use of reactors, but they're an extra expense, and they take up room that is often not available.

3) Far too often, a VFD is used to atone for a bad mechanical design. And even if the VFD somewhat solves the problem, the mechanical issue still exists. I can't think of how many VFDs I've seen that run at 60HZ continuously because some dope tried to solve a design issue with a VFD.

4) Unless a VFD is grossly oversized, the motor it drives has far less starting/pullup/breakdown torque than if it were operated across the lines. Most VFDs can produce about 250% of their rating, a motor would like to see more like 600% for starting. Even though I make it completely clear that adding a VFD to a motor won't work, since I installed it, I'm the one who is blamed when it doesn't work.

5) Programming the vast majority of VFDs is somewhat of a nightmare. They need to be made MUCH simpler. And the manuals need to be written in plain English, not a bunch of technobabble that no one can understand.

6) They add a huge amount of heat to an electrical room.

7) About 2 or 3% of the VFDs I install have some sort of factory defect. Some manufacturers are pretty good about sending new cards and such, others are nearly impossible to deal with. In my experience, the majority of factory techs are nothing more than educated idiots with electrical engineering degrees and absolutely zero knowledge of anything.

Even with that being said, they certainly do have their place, and properly applied, they can make the overall design and operation of a lot of stuff much simpler.
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Old 04-14-2013, 12:29 PM   #12
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Electric motor crossover.


Quote:
Originally Posted by micromind

Several reasons;

1) They cause harmonic distortion in the incoming power source. This is rough on motors and transformers. The waveform just about anywhere (VFDs present or not) is getting more distorted as more VFDs are installed. Nationwide.

2) They're rough on motors. Unless the motor is wound with spike-resistant wire, a VFD will wreck a motor, worse if there's any distance between the VFD and the motor. Reflected power causes voltage spikes that jump between individual wires in a winding. This can be solved by the use of reactors, but they're an extra expense, and they take up room that is often not available.

3) Far too often, a VFD is used to atone for a bad mechanical design. And even if the VFD somewhat solves the problem, the mechanical issue still exists. I can't think of how many VFDs I've seen that run at 60HZ continuously because some dope tried to solve a design issue with a VFD.

4) Unless a VFD is grossly oversized, the motor it drives has far less starting/pullup/breakdown torque than if it were operated across the lines. Most VFDs can produce about 250% of their rating, a motor would like to see more like 600% for starting. Even though I make it completely clear that adding a VFD to a motor won't work, since I installed it, I'm the one who is blamed when it doesn't work.

5) Programming the vast majority of VFDs is somewhat of a nightmare. They need to be made MUCH simpler. And the manuals need to be written in plain English, not a bunch of technobabble that no one can understand.

6) They add a huge amount of heat to an electrical room.

7) About 2 or 3% of the VFDs I install have some sort of factory defect. Some manufacturers are pretty good about sending new cards and such, others are nearly impossible to deal with. In my experience, the majority of factory techs are nothing more than educated idiots with electrical engineering degrees and absolutely zero knowledge of anything.

Even with that being said, they certainly do have their place, and properly applied, they can make the overall design and operation of a lot of stuff much simpler.
Having been in the industry for 35+ yrs myself, back in the days when they were only SCR six step square wave based designs, I have to agree with your opinions. They've come a long way but you are correct.
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Old 04-14-2013, 07:06 PM   #13
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Electric motor crossover.


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Originally Posted by 64pvolvo1800 View Post
Having been in the industry for 35+ yrs myself, back in the days when they were only SCR six step square wave based designs, I have to agree with your opinions. They've come a long way but you are correct.
Yep, the old 6 SCR firing type was pretty rough on any motor.

They have come a long way, but they still have their share of problems.....

Remember the Saftronics VFds? One plant I work at has about a half-dozen of those still in operation. Hard to believe they'd last that long.
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Old 04-15-2013, 11:20 AM   #14
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Electric motor crossover.


So. We should revert to DC as AC is to complicated?

While many of your statements are true. There is no other way to vary the speed of an ac motor without a VFD. Thus eliminating the need for expensive DC motors.

VFD's allow for PID control and speed regulation on many industrial applications.

I for one like VFD's and used them regularly in industrial applications.
I also find VFD's easy to program and understand. AB and others have over complicted a parameter set that could be accomplished with a few pages of instructions and programming. Baldor had this idea to simplify the programming (real english, no code numbers) but they are now Reliance.

Thanks for responding as I have always wondered why you felt this way.

I for one will use them and recommend them to customers to take the place of DC motors and in any application where speed control and precise monitoring and process is required.
You could not use across the line for servo motors. We need these machines to build and make the things we use every day.
Variable speed and control are what we use to make everything from cars to plastic spoons and forks.

We must make sure we do not dismiss VFD's and their cousins as no across line starting can do these things.

I also feel the same way when it comes to soft starts. Electronic SS's are the way to go. Even on smaller frames as the price has gone down and in many cases are less expensive than NEMA contactors.
SS's save wear and tear on motors and are smart enoug to bypass the control once the selected speed is achieved.
I approve and support progress.


Last edited by J. V.; 04-15-2013 at 11:27 AM.
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