Drives at motor's starting up

[lume7006]

Hello,

I hope you are fine!

I am new on the "drives field" and I would like to get some
information about the way drives (any manufacturer) are set to allow motor starting.
What I mean is:
What are the typical parameters that drives request to program the motor starting?
I think there should be some parameters like some ramps, time constants and so on.

Any information will be welcome because, we already search through some manufacturers web site unsuccesfully.

Best Regards,

 

[ozmosis]

It would help if you were a little more specific. For a start, AC or DC?

 

[sreid]

All AC drives I have used have had acceleration and deceleration ramp parameters in the form "Seconds to requested RPM."

 

[lume7006]

Hello,

I thank your answers!

We are analysing the starting up of some AC medium voltage motors.

We have already tried to get something from the manufacturers website unsuccesfully and we would like to know what are the parameters to be set for starting up!

I will thank your additional comments

 

[jraef]

Sad that you have apparently purchased a very expensive medium voltage drive and must resort to a website for commissioning information. With Medium Voltage drives, this is something usually performed by experienced professionals under contract.

 

[drillz]

the only problem with start-up, is that of burning out the windings due to the fact that a stationary motor is not yet generating enough back-EMF to "reduce" the supply current.

I would get a current clamp round the motor supply and see how much it gets up to with slowly increasing start-up times.

 

[DickDV]

lume7006, with a medium voltage drive, it is essential for performance and especially safety to have a factory-certified technician do the commissioning.

Do not consider any other alternative. Lots of money and life and limb are at stake.

 

[ozmosis]

lume7006
What do you mean by a Medium Voltage "Drive"? Do you mean a variable Frequency drive or Electronic softstart? Sometimes the phrase 'drive' can have a number of meanings.
However, whatever it is on MV, you should have a warm body next to you from the supplier who knows what they are doing, to assist you. Doing things wrong on LV creates enough problems but on MV it is a whole different ball game.

 

[lume7006]

Hello everybody,

I thank your comments and ideas that are always helpfull to us!
You have given us some material to think!

I must clarify that our main goal at this moment is knowing at detail the parameters that a drive (frequency drive) typically needs for motor starting.
We are in the process of evaluating drives performance using some dynamic simulations and based on that making a decision about the use of a drive or a softstarter or some other method for a medium voltage motor. Our key point is starting up at this moment.

Because of that, we would like to receive your feedback about some source of information or from your experience what are the typical parameters that a drive requires for an AC motor starting up.
We need to know the parameters (ramps typically) their ranges, restrictions and so on.

Have a nice day!

 

[sreid]

The drive I'mm working on right now (1500 Watts) allows 0 to 20 seconds. For fast accels, the accel is determined by current limits.

VFD are usually used when variable speed is required.

 

[boaterbill]

The mechanical inertia needs to be determined.
A soft start will reduce the strain on the mechaincal equipment as the unit is ramping up. A VFD will operate the motor across different speeds to operate in the process more efficiently.
Contact Robicon or Allen-Bradly for the medium voltage info. It is WAY too dangerous not to do without years of experience.
Good luck

 

[TomG33]

There are many parameters that need to be set to match a drive with a motor, and application.
Some of the primary type parameters you are looking at are things such as

Supply Volts
Supply Frequency
Supply isolation Transformer size.
Control power voltage level

Motor volts
Motor Frequency
Motor Base speed
Motor Top speed
Motor Rated Amps
Motor Rated power.

Load inertia
Load Acceleration and deceleration time
ALternative ramp time (emergency stop situation)
Load Rated Speed (may not be the same as the motor)

Method of communication to supervisory control
Hardwired Control ?
Serial Link Control ?
Communication Protocol?
Hard wired Emergency stop requirements

Hard wired input specification
Hardwired output specification

.....
.........
............

These are some of the ones I can think of while just sitting here. Imagine how many there would be of I was to do the job properly as a good commissioning engineer should?

The names and function will change from manufacturer to manufacturer, so do not expect to find the same parameter name in a European Suppliers equipment as you would on say a japaneese or American built piece of gear.

I hope that this highlights the thihgs others have said here already,

LEAVE THE JOB TO SOMEONE WHO KNOWS WHAT THEY ARE DOING!!!!

THe Drive manufacturer, The equipment OEM, The Customer Should all have their own little bits to specify in order to get a control system working correctly and safely with the equipment it is driving.

If you are serious about purchasing a MV Drive, I am sure the various manufactures would be falling over themselves to try to help you sort these things out.

Tom Grayson