one phase or 3 phase motor? 3

[lukin1977]

Dear experts

I am building a machine that will make 1 kg wire coils from 25 kg large coils (recoiler)

The motor will be 1HP and it will start and stop every 30 seconds. My question is: Should I use a one phase motor or a 3 phase motor? Witch are the chosing factors?

 

[Brad1979]

You should use whatever voltage you have available to run it with. If you have both available, you'll probably want to go with 3 phase.

 

[waross]

For that duty I would suggest a three phase motor and Variable Frequency Drive combination.
A 30 second duty cycle is harsh on either a single phase motor or a three phase motor. The VFD will start the motor with much less heating and in addition you will have programmable acceleration and de-celleration ramps. You will also have the advantage of speed control.
If you don't want to use a VFD I would suggest a three phase motor. Less moving parts and often better starting torque. The better starting torque means faster acceleration which may mean less motor heating during starting.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[jraef]

I would not do a winder without using a VFD and 3 phase inverter duty motor now, they are too simple and cheap NOT to take advantage of them for this type of application.

But I'll also chime in with Bill, go 3 phase if you are not going to use a VFD. 1 phase means you have starting switches and capacitors that will get very stressed from the duty cycle and will be a primary point of failure earlier than anything in a 3 phase motor.

"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
For the best use of Eng-Tips, please click here -> faq731-376

 

[electricpete]

Some guidance for repetitive DOL starting

http://www.joliettech.com/allowable_starts-intervals.htm

Column A is starts per hour. The highest number anywhere on the chart is 34 starts per hour (one per two minutes)

I tend to think when you start crowing the starts too close together the failure can be short-term rather than long term when you reach the melting temperature of aluminum.

=====================================
(2B)+(2B)' ?

 

[itsmoked]

You may be able to deep-six that lousy abusive duty cycle and run continuously but slowly with a VFD. Might need an additional fan for cooling.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[lukin1977]

I was thinking this option too:

Use an electric clutch so I dont have to stop the motor every time the coiler finish to wind. The start and stop will be done with the clutch and the motor keeps running

what do you think?

 

[waross]

The clutch is an "Old school" solution. For many decades the solution of choice would have been a clutch. It will still work well but we now have the option of using VFDs.
Note: Small (1 hp) VFDs are available that are capable of running on a supply current that is either single phase or three phase.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[lukin1977]

I understand. So the VFD wont have any problems handling this kind of duty?

 

[cswilson]

Unlike a DOL motor, a VFD inverter does not dissipate additional heat at low speeds, so frequent starts and stops are not an issue.

If you were to go all the way to a sensorless-vector or servo drive and use very aggressive acceleration and deceleration settings, the high current during the ramp up and ramp down might have to be analyzed, but even in this case, a couple of seconds of high current out of a 30-second cycle would probably not be problematic.

Curt Wilson
Delta Tau Data Systems

 

[DickDV]

With a VFD and 1 hp motor, I would recommend choosing a TENV motor. It cools better and has no external or internal fan to clog up and make trouble.

 

[lukin1977]

I dont think that I would find a TENV Motor here. What I did find is a motor specially designed to be used with VFD. Motor brand is WEG - type IFW and I already have a VFD. VFD brand is Lenze - Type 8150

 

[DickDV]

OK, lukin1977. Use the motor you have. But if and when it overheats from frequent starts and stops, you just might remember to look for a Totally Enclosed Non Vent motor. It doesn't have to be NEMA. They are available around the world in IEC frames as well.

The main difference is that the cooling doesn't depend upon a shaft-driven fan. The motor cools as much standing still as running full speed.

Watch for it!

 

[starkopete]

lukin1977,
DickDV knows what he speaks of...consider what he says.

 

[lukin1977]

DickDV and starkopete

We will do some tests with our existing motor because we already have it and we dont use it for anything else and I am getting in touch with a TENV motor seller too.
It will take some time before we have the TENV motor in our factory

Thanks to all for your help. I will comeback with news after the first tests are completed

 

[DickDV]

feedback is a very welcome thing here, lukin1977. Yes, let us know how things worked out. And, good luck.

 

[akselj]

You should consider an external cooling fanfor the motor.