Repair vs Replacement policies

[Steventyj]

I would like to thank everyone for the help I have recieved directly and for the knowledge I have gained by reading other peoples threads.

I am wondering how companies make replace or repair decisons for thier electric motors. As far as I can tell the following would be factors in the decision:

- Size of the company - A larger company may want a strict rule to save time (eg a hard set HP break point)
- Cost of Electricity
- In house or vendor repair shop
- Cost of downtime/critcality of motors to the operation of the plant
- Age of motor
- Repair work needed


Is it common that a company will make a policy to only consider repairs on motors above a certain HP? I have not worked for enough companies to know if this is a common approach.

Thanks in advance for any feedback.

 

[jbartos]

Suggestion: Generally, if the cost of the product is relatively low and there is a product warranty, and something goes wrong with the product, then the customer returns the product. The supplier/manufacturers decides about the repair or replacement by a new product. I had about @200 external CD-RW and it malfunctioned. I returned it and I got a different one, a brand new one.

 

[dadfap]

steventyj

Initially the cost is solely economic, hence the common wording in terms & conditions "repaired or replaced at the manufacturer's sole discretion" The key is sole discretion, because although economic justifications play a part, customer relationships also play a part.

It comes down to labour & parts costs vs the simplicity of replacing the item. The manufacturer will also take into consideration the fact that he will regain ownership of the defective item, motor in this case, and can rework it.

Probably not the answer you were looking for, but we manufacturers are always looking at
1. How best to satisfy the warranty claim
2. The significance of the customer to our business
3. Cost effectiveness of what we do


So, the answer is always going to be different from each manufacturer.

dadfap

 

[Steventyj]

Sorry, I think my question was misunderstood. When I said companies I meant end-user companies. As in, what does a mill do when they have a 6 year old motor (no warranty) that fails.

 

[electricpete]

For large motors (above NEMA frame) we always rewind. It is a no-brainer since the cost is approx 1/2 of a new motor and these large motors are typically not available off the shelf.

For small fractional motors we always replace, if they are available off the shelf. Not cost-effective to rewind the small motors.

For medium motors it is a grey area and we handle on a case basis. Typically 100hp or larger we will rewind.

 

[joepower]

Try the flowchart at

http://www.easa.com/indus/rr0601.pdf

 

[jbartos]

Suggestion: Sometimes, even small motors are rewound if they are atypical, not available off the shelf.

 

[GusD]

Hi Steventyj

The answer to your question is very subjective.
We had to repair a 1250 hp motor,that we had decommissioned 2 years prior.The stator had burned up when rotor contacted stator laminations.Motor had to have
the cores restacked and stator rewound.I don't have to tell you that it cost us more than we would have paid for a new one.Problem was,we could not have got a new motor in less then 6 months.In this instance we had no choice.
Electricpete's policy for the large motors makes alot of sense.Jbartos small motors that you must have today or shortly also makes sense.
If you can purchase a new motor off the shelf,and its cost is only a 3rd higher than a repair,we would purchase the new motor.

GusD

 

[jraef]

Another factor to consider is the type of motor involved. If you are using the newer energy eficient motors, the cost to rewind anything 50HP and under is now usually prohibitive. Proper rewinding requires high temperature bake-out and specialized balancing and coating systems which are all very expensive for the rewind shops. Few are therefore willing to invest, which limits competition, which drives up costs (I learned that in Econ 101 some years back).

In addition, many utilities (in the US anyway) offer rebates for replacing older motors with newer energy efficient ones, and many users take advantage of that fact when an old motor goes down.

60HP through about 150HP becomes a cost/benefit issue related to the confidence you have in the motor shop and the length of downtime you will experience. 200HP and up almost always favors rewinding unless it is critical-path equipment, in which case you should have spares anyway.



Quando Omni Flunkus Moritati