I'm not sure if I'm posting this at the right board.

Could someone please indicate me what are the preventive maintenance tasks for ac motors, including those related to CM?

I need to device a strategy for a critical ac motor and wish to evaluate all methods. Thank you.

I'm not an motor expert but if you provide more information on your motor others may provide you better advise. Your motor is:
* Single or Three Phase
* Synchronous or Induction
* Wound Rotor or Squirel-cage

Eugene,

I am sorry but I cannot answer your second and third question because I do not know?

All I know is that the motors (there are 3 of this type on HVAC units) are three phase and are controlled via a frequency inverter to meet the modulating load.

Besides the manufacturer, type and serial number, these are the details from the name plate:

Cos phi: 0.86
Efficiency Class: 2
IP 55
Power at 50hz: 30Kw
Insulation Class: F
Voltage: 690/400 V
Current: 30.6/52.8A
Speed 1470rpm


I'd appreciate some advise. Thank you.

These are 30kW, 3-phase, AC, 4-pole, IEC machines.

How critical are the HVAC machines? What type of coupling?

In any case, I have a series of free papers, presentations, etc. on my site, as well as those you can find in the motors section of http://www.reliabilityweb.com.

My series of papers and documents can be found on http://www.motordiagnostics.com/presentations.htm. The ones that I recommend are:

• Motor Diagnostics and Motor Health Study
  
• Greasing Electric Motor series of papers
  
• FEMP Operations and Maintenance Manual
  
• RCM-Based Motor Management Presentation
  
• A Novel Approach to Electric Motor System Maintenance and Management for Improved Industrial and Commercial Uptime and Energy Costs
  
• AC Motor Testing and Predictive Maintenance
  
• Developing a Motor Management Program
  
• Penrose Lecture Series papers - cover all the topics that you requested including how to develop repair specifications.
  
  

The earlier papers have older contact information for me. If you (or anyone else reading) have any questions on these documents, please feel free to contact me at howard@motordoc.net.

Sincerely,
Howard

Dear Howard,

Thank you for the information.

Does anyone can indicate me a failure rate for these motors (HVAC fan, belt driven)?

cheers

Rennie this is a difficult subjet, the failure rate. It varies with the skills/knowledge/motivation of the craftsmen working on the system.
If the guy is not trained and only go with the "universal basic toolbox" he will install the belt using the big screwdriver and stop the noise with belt dressing. Observing what they do and how, and ask their opinion will lead to wealth of information.

Rennie, I just changed frequency for checking HVAC fan belt, fan, filter from 6 monthly to monthly recently as requested by offshore in the absence of failure rates.

But what where the experience with the 6M frequency? I would increase PM frequency (6M to 3M or 1M) only if every time I inspect a unit there are problems to fix or corrective work within the 6M period is high.

On the other hand, if I execute a PM every 3M and every time all is ok I would consider to reduce the PM to 6M inspections.

The same opinion I have, the danger is that if they look at the equipment too much, they will not notice any sign, especially if the unit has a history of absence of failures, and start skipping...

Points noted. There should be justification to change eg repeat malfunctions but on what basis was the original 6M frequency set?

quote:

on what basis was the original 6M frequency set?

I am not there!!
But

quote:

as requested by offshore in the absence of failure rates

My blunt opinion is: they have too much time. I didn't meet the craftsman yet, requesting more work when everything is cool.

But wait
1) It is HVAC equipment (probably designed in the USA), An engineer who only knows snow and ice, and never have been close to the equator....(6 months)
2) Offshore means salt water?
3) Borneo (rainforrest, moessons)
4) Is the work done by a contractor?

I would conclude that the contactor or whoever is doing a lousy job based on maintenance rules which are valid for New York, but a disaster in a region with >80% humidity, combined with the agressive atmosphere of seawater, and they are not reporting it in the CMMS!!

We have a few problems with the fan belts & to check filters more frequently by inhouse personnel. Also the personnel did the same frequency for air-cond in another company working in the same climate. How often do you check your aircond?

If you have outsourced HVAC to a contractor and the inhouse crew starts doing monthly PM, there is something awfully wrong. That means the quality of work delivered is not up to standards, we outsource because we don't want the headache, don't have the experience, or the (human) resources.
Points I would consider:
1) Are the equipment on both sites the same?
2) What is the response time of the contractor for both sites?
3) Does the contractor has enough resources to guarantee the service to both sites?

Probably at the site with the best service the checks are signed

Agree with your views but did I say we outsource the HVAC? I mean the inhouse personnel has worked for another oil & gas offshore company before joing the present oil & gas company.

Josh, it can be that the workers are good, but you failed to get "the brains" working for you.

In other words, people will only be top performers, if there is a good system in place to back them up.
CMMS, procedures, "Plan-Do-Act" etc..

Probably the guys from the other company, were not that high in the food chain...

What is your point here? You seem to be rumbling...

Jumping from a 6 months PM to monthly PM, without justification, any maintenance guy would raise his eyebrows, a v-belt inspection every month? Filters I could imagine in a dusty atmosphere to clean them every 2 months.
I rather find it suspicious.

Ok, I keep your concern in mind, if nothing is detected during the one month, increase to 2 months then.

Btw, who has the MTBF for HVAC system? What is the failure pattern for HVAC?

"if nothing is detected ???"

In my opinion Preventive Maintenance includes a task where somebody has to do something.
If he is only looking (inspecting) at the equipment, it would be cheaper to put a camera watching the equipment 24 hours.

What we understand PM includes operator check, performance monitoring, visual inspection, etc in addition to hands on tasks.

Do you use a camera to monitor the air cond of your office?

This message has been edited. Last edited by: Josh,