When to Megger Motors

[SparkyLarks]

I work for a company that makes a small number of machines, and does work CE Marking third party machines.

EN60204-1 says that you may need to perform Insulation Resistance tests but gives no guidance on when you may need to perform them. I'm trying to develop a few guidelines on when we should perform insulation resistance tests. (Customers won't pay us if we price in insulation resistance of every Transformer, motor, and cable)

We sometimes are asked to CE new machine imported from the US, or Check compliance of old machines. Legally the requirement for insulation testing is determined by the risk assessment. But I can't say to customers I need to test all motors, even 50W motors.

One suggestions was if you can't lift it , then Test it
I was thinking of proposing
1) If a cable is longer than 20m then Test it
2) If a cable carries greater thatn 63 A then Test it
3) Motors >25kW then Test it
4) Transformers > 10kVA the Test it

Does that sound reasonable?

We would of course be recommending that the customer should test motors and transformers as part of routine maintenance.

We will bench test motors and transformers for machines we build ourselves. Cables we install on site will also be IR tested( Part of the legal tests required for installations.)

 

[KllrWolf]

I work for a fluid filled submersible motor manufacturer and repair shop.

The smallest motor we deal with is 5 HP and we meg them. We also meg test any cable that passes through here.

A basic test only take a few minutes and we consider it part of our cost of doing buisiness. It is not worth our reputation to send something out that does not meet our standard of quality, even if we are not the manufacturer of the item in question.

My recommendation is that if you can safely test it, test it.

 

[Motorwinder]

Let the customer decide which motors are the most critical to there operation. We have a customer that wants all his motors megged from fractional to 500 KW. This with a vibration analysis is done on a yearly basis.

 

[sanugw]

Most Customers i worked with wanted these tests done before installation on all systems regardless of the rating requirement, doing this for all instances regardless of the ratings will also enable you to make it a part of your service agreement that the customer will pay for during maintenance.
Making up the cost of doing it on systems upfront !!

My 2 Cents

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