Wide Range Multi-Voltage Motor Test Panel Master Contactor

How do you know that there will be a size of fit issue?

Also I don't understand what your referring to in regards to a contactor being too big for a motor?

Given that it will be supplying several different voltages it will need several different supply sources or a large three phase multi tapped step down transformer for the voltages below what ever the main supply lines are.

To me there is not enough information to accurately understand what it is exactly you are needing. Or else you don't have the full understanding of whats required or involved on the construction of a 120 - 575 volt single/three phase multifunction power source with a top end capacity of around 120 KW.

Firstly, the amount of space allotted is known, and it is not enough to accommodate a conventional MCC, which would require a combination motor starter for each individual motor and variant, of which there are 10 models with these models having variants involving the voltages given (thusly, load and short circuit currents).

So, in the interest of size reduction, this would require ADJUSTABLE overload and short circuit protection.

As to the contactor being too big for the motor, contactors are designed for a specific motor load range, whereby the INRUSH and disconnect under load currents actually provide a clearing action on the contact surfaces. Under-size loads can cause build-up of deposits on the contact surfaces, which can cause other problems. Anyone with experience in the motor control field will know what I am talking about.

As the motor under test, will be attached to the common buss I mentioned, the master contactor will be slaved to the safety interlocks and the adjustable overloads.

Perhaps I did not make myself clear, but my question involves what type of contactor or disconnecting means that would assure disconnect of the power to the motor, without the possibility of contact welding due to undersized load.

The fact that the panel will need multiple voltage sources is obvious even to most casual observer.

Test panels are a "gray area" when it comes right down to it, but I think I have a reasonable understanding of what is required, as I have been involved with motors and motor control for about 30 years.

Have a look at the following document, which might be the solution for your problem: http://www.kistler.com/mediaaccess/300-604e-06.08.pdf Best regards

Thanks Kunomars,

Those are nice test fixtures, but I am primarily interested in the motor control.

Ooooooh! Can I have one for christmas?

Chas

First,i dont see any significant drawback in d said Master Contactor to disconnect lesser load,if that is yr only problem with yr required test panel.It is unnecessary cost using oversized contactor to power small loads.

Now to yr question,MCC is out of this.U need a special design cct for d job.Uwill need a few cct compartment(say 4nos) in the panel.One compartment controls d single phase 1-4kw motors for tests,while others controls a set of range of 3 phase kw motors.

U will buy a breaker with wide range of selectable short-cct and overload settings.This will handle(ie test) say between 1.5kw to 11kw 3 phase motors,while another higher,but wide range device will handle(ie test) say between 15kw to 37kw motors,and then 45 to 132kw motors with another higher adjustable range of breaker.

This is a simple design.It is not complex.If u hv d knowledge of power and control cct design,u dont need to look for,but to buy yr components,suitable empty panel and buid it yrself.I can easily handle this project wt any extra functionality required by you,bt we are far apart,so look for a good power and control design specialist in yr area and get yr job done.

Note that if there are several sources,u must interlock yr ccts either electrically or electronically.Remember also that yr small motors will run on DOL and large kw motors on STAR-DELTA starter.Further questions on my comment is welcomed.

Patrick Whowha

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