Spare motors for the 40 year old equipment

[krisys]

We have forty (40) year old Frame-5 gas turbine generator (GTG) units in our site and still operating. As the units are old, failure rates are slowly creeping up. At this stage the original spares are exhausted in our stores. However, sourcing these spares have become very difficult. Either the models are not being manufactured any more or the sub-suppliers are not existing.

We have to procure the following motors:
a) Two (2) DC 125 V motors (one 5 HP, Frame NEZ D 160 and the other is 0.75 HP, Frame size 74)
b) Two (2) AC motors 415V, 3 phase 50 Hz (one 30HP, 2900 rpm, E200LD Frame and the other is 5HP, 1450 rpm, 184T Frame).

I have a challenge in procuring these motors.
a) I feel the AC motors, appear to be having the standard Frame size and hence should be able to procure them from the open market (any manufacturer). Is my assumption correct?
b) How to source these DC motors? Any suggestion or experience to share with?

 

[edison123]

I see that Scotty beat me to it as usual.

Muthu

http://www.edison.co.in

 

[ScottyUK]

The ones I've worked on range between 20HP and 60HP, depending on machine size. I'm sure there are smaller ones, there are very probably bigger ones too. Typically fed at 110V DC or 220V DC from a substantial battery.

 

[edison123]

Keith - The one we did was 220 V, 30 KW DC motor.

Muthu

http://www.edison.co.in

 

[davidbeach]

I know of failures we have had without knowing all the details. But when the AC lube system fails, I know for absolute sure you don't want to also see a DC lube system failure; I know where to find those in the events records... I wrote up the "and it failed to start" entry, but wasn't involved in the nitty-gritty of the multiple steps that lead to it not starting or not continuing to run.

DC lube system failures generally occur because some system condition is outside the tolerances anticipated by the initial designers. If you need staged starting, so be it, but a DC system that simply sees a lack of pressure, for any reason, will be more robust than a DC system that looks for certain AC system conditions before starting.

 

[edison123]

Lack of pressure, oil flow etc. are already monitored in AC lube oil system also. Reason why DC motor is not continuously run is due to maintenance, brush wear etc.

Muthu

http://www.edison.co.in

 

[krisys]

The subject Lube oil pump motor in question is 5 HP.
This GTG has shaft driven Lube Oil pump which is normally pumping Lube oil while the machine is normally running.

The auxiliary Lube oil pump motor is 400V, 50Hz, induction motor supplied from emergency DG. This will be running during the start up and normal outage, when the mains power is available through other GTGs. This motor is not a continuous running.

The DC Lube oil pump motor in discussion (5HP, 220V DC) is for the back up pump. This will normally start only when there is a total black out. It will be running until the Emergency DG kicks in and restores power to the emergency MCC. This motor is running only during contingencies and the duration of running is very short.

The starting of AC auxiliary Lube oil pump and the DC Lube oil pump motor are based on the pressure. When the Lube oil pressure falls to the first setting the AC auxiliary Lube oil pump will start. If it fails to start, the pressure would go down. When the pressure falls to the second setting, DC Lube oil pump motor.

Academically, this is a good discussion. However, I have a mandate to maintain the existing philosophies and the system. So my task is to source the 5 HP 220 VDC motor. The physical dimension and the operating characteristics of the motor shall be exactly matching with the old motor.

In fact when the motor in service fails I should be able to replace the faulty motor with the new motor, by removing the cable connection and by removing the four bolts!

Is there any motor vendor (reputed) who can supply such motor

 

[sreid]

Peerless Electric

http://peerlesselectric.com/

 

[waross]

In fact when the motor in service fails I should be able to replace the faulty motor with the new motor

"In fact when the motor in service fails..." you may have a bigger problem than may be solved by "removing the cable connection and by removing the four bolts!"

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

 

[ScottyUK]

One of the few I've identified so far -

https://www.w-winkelmann.com/

 

[waross]

Is it acceptable to supply a complete pump assembly, with equal or better performance than the original?
Contrast that with the cost of shipping an existing pump to somewhere in the world where it may be rewound?
India comes to mind as a possible option for repair.

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

 

[DAVIDSTECKER]

For the AC motors I would recommend Reuland Electric.
Really good at one off custom motors.
My contact their gave me the name T-T Electric USA for DC.

 

[Hoxton]

Well, you could ask a surviving support company. If they cannot help you, no one will!

I have no connection to them!

http://www.johnbrown.eu/index.asp

 

[krisys]

Hexton,
Thanks; as you mentioned we are now trying to contact the surviving support company. In the meantime, we are exploring other option as well.


If I consider the replacement with pump, then the job becomes multi disciplinary involving rotating machineries, piping engineer etc. We want to make the job a stand alone for electrical discipline only.

Thanking all for sharing your views so far.

As the time progresses I will keep posted on how we are proceeding.

 

[waross]

A possible solution may be to upgrade one or two Turbine Generator Units with new pumps during normal scheduled downtime rather than waiting for a failure.
That will give you one or two sets of spares that will cover you well into the future and avoid a lengthy, unplanned shutdown.
Many would consider these Turbine Generator Units to be past the end of life.
Many management philosophies would dictate that these machines be replaced with new units now.
Other philosophies will keep these machines running and avoid the expense of new replacements as long as possible, however that may require some compromises from historical maintenance and repair methods.
These units may serve well into the future if some flexibility in care and repair is allowed.
Yes, I know, it is not our place to challenge management philosophy.
The challenge, which may be a greater challenge than procuring spares, is to somehow drop hints to help management to figure this out themselves without negatively impacting any careers.
Good luck.

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