The Electrical Contractor Network

ECN Electrical Forum
Discussion Forums for Electricians, Inspectors and Related Professionals

Books, Tools and Test Equipment for Electrical and Construction Trades

Register Now!

Register Now!

We want your input!


2017 NEC and Related
2017 NEC
Now Available!

Recent Posts
Son of Sparky
by HotLine1
Yesterday at 07:43 PM
Speaking of Plugmold ...
by gfretwell
10/17/16 02:37 PM
Broken battery charger? Check for cobwebs!
by gfretwell
10/17/16 02:30 PM
230 or 345 kV transmission lines?
by annemarie1
10/12/16 01:23 PM
Is this a fix or just a bandaid?
by gfretwell
10/10/16 06:49 PM
New in the Gallery:
12.5A through 0.75mm˛ flex (just out of curiosity)
Shout Box

Top Posters (30 Days)
gfretwell 11
renosteinke 6
HotLine1 6
ghost307 5
Potseal 4
Who's Online
0 registered (), 54 Guests and 4 Spiders online.
Key: Admin, Global Mod, Mod
Topic Options
Rate This Topic
#162354 - 04/18/07 12:44 AM AC Motor Maintenance (3phase/1phase)
roland12 Offline
New Member

Registered: 04/02/07
Posts: 2
Loc: philippines
hi guys! pls help me
how can i maintain a 3 phase/1 phase motor
preventive / corrective if any.
thanks in advance.

#163214 - 05/03/07 10:36 PM Re: AC Motor Maintenance (3phase/1phase) [Re: roland12]

Registered: 12/08/05
Posts: 862
Loc: Titirangi, Akld, New Zealand
Hi roland12,

Keeping the air vents and cooling fins clean off debris, so the motor can dissipate it's heat.

Check that the machine it is driving, has no binding rotating matters which could slow the motor down, or make starting more difficult.
Do a load check when the machine is running and check that the current measured, is within the nameplate rating.
Check mains voltage too. Undervoltage to motors will reduce starting torque and may cause a motor to stall and burn out prematurely.
Check thermal overload settings set correctly.
Check fusing. Correct size, motorrated.

When fully isolated from the supply.

Check end play on bearings.
Do an insulation test on the windings.

Hope this will help

Kind regards, Raymond
The product of rotation, excitation and flux produces electricty.

#163222 - 05/04/07 04:25 AM Re: AC Motor Maintenance (3phase/1phase) [Re: RODALCO]
WFO Offline

Registered: 09/03/05
Posts: 206
Loc: Cat Spring, TX
On the 3 phase, make sure your voltages are balanced as well. A small imbalance in voltage will cause a large imbalance in current.

#163286 - 05/05/07 11:19 AM Re: AC Motor Maintenance (3phase/1phase) [Re: roland12]
renosteinke Offline
Cat Servant

Registered: 01/22/05
Posts: 5305
Loc: Blue Collar Country
There's not a lot to worry about ... as far as the motor itself is concerned. The right motor, installed correctly, will not only run darn near forever ... it will give lots of warning when it's getting tired.

There are three phase of maintenance:
1) Verify the selection;
2) Check the install; and,
3) Keep testing records

You verify the selection by comparing actual voltage and amp draw to the nameplate info. Check the running temps. As Rod said, keep it clean.

The motor has to be properly mounted, with the shaft/sheaves properly lined up. Belt/chain tension ought to be correct.

If you have a megger, there are a series of tests you can perform. These tests, for the most part, begin when the motor is new, and are periodically repeated. Comparing the results over time will give you ample warning that the motor is about to fail.

#163367 - 05/07/07 01:33 AM Re: AC Motor Maintenance (3phase/1phase) [Re: renosteinke]
pauluk Offline

Registered: 08/11/01
Posts: 7693
Loc: Norfolk, England
From Alan Belson:

How long can a motor last? This is the original 400v 'Drouard' 5hp 3-phase 6 pole 900 rpm motor running my ancient bandsaw. Renovated a couple of years ago, this machine is in constant daily use. Built in Paris about 1931. I think you are supposed to re-grease the bearings on these old motors every 20,000 hours.


ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals