Trouble with a 3 phase motor | on ElectriciansForums

Discuss Trouble with a 3 phase motor in the Electrician Talk | All Countries area at ElectriciansForums.net

N

nicky123

Here is mty problem:

3-Phase motor for air extraction


Motor 1:
220/440 Y V
HP:5
I: 15.8/7.9 amp
RPM: 1740
FP:0.78
n:79.4%
Tn/To: 20.4/47nm
FS 1.5


Motor 2:
220/440 Y V
HP:7.5
I: 21.8/10.9 amp
RPM: 3480
FP:0.87
n:77.4%
Tn/To: 20.4/47nm
FS 1.5


Problems:
1. The motor 1 was burned out after one month running because electricity failure ( the motor was single phasing; problem with the electricity supplier )
2. The motor 1 was not extracting enough air.
Solution:
1. The electricity problem was fixed by installing some component to avoid working with 1 phase.
2. Motor 2 was installed.
3. The motor 2 now is extracting enough air.


Poblems:
1. After one day running, the motor 2 burned out.
Solution:
1. Motor 2 was rewound with the same characteristics of motor 1. The motor is now running without problem since 2 month ago.


Problems:
1. Is not extracting enough air.


Overall, is seems like the extractor is working ok with motor 1 but is not extracting enough air, but with a motor 2 is extracting enough air but burned out after one day running.


Aditional data:
1. The motor is fed by a transformer of 30kva, this transformer also fed an air conditioner of 60.000 BTU/h and others minor electrical appliance.
2. The extractor was installed to extract air using 15m of duct.
3. I have no data about cfm or pressure required.
4. The extractor is 30'' size.


Questions:
1. Possibles causes why motor 2 burned out.
2. How can i know which motor fix ?
3.Possibles solution to make the extractor to extract enough air.
 
You haven't given us your location and 3ph voltage in your area?
You haven't told us how you motor is connected (star or delta)?
You haven't told us how your starting your motor?
Why are your motors burning out, where's your overload protection and what is it set at if you have?
Have you measured the current on each phase when the motor is running

Just a few questions to start the ball rolling, motors burn out for numerous reasons so asking that question and just showing us plate details wont give us any clues, is the impellor running free and clear of ducting (not catching and jamming)... the voltage needs to be checked when air con is on and loaded up also current demand on transformer.

And lastly what is your background so we can adapt our answers and questions to your level of knowledge.
 
No mention whether the other loads are three phase but I would think that the air con is three phase at 17.6Kw

Could be one or more problems here but again there is a lack of info or pics
 
A make and model number for the fan would be helpful.

Why would the fan have a second motor that's completely different to the first one?

If any motor burns out due to mechanical overload or phase failure then the protection is incorrectly designed.
 
You haven't given us your location and 3ph voltage in your area?
You haven't told us how you motor is connected (star or delta)?
You haven't told us how your starting your motor?
Why are your motors burning out, where's your overload protection and what is it set at if you have?
Have you measured the current on each phase when the motor is running

Just a few questions to start the ball rolling, motors burn out for numerous reasons so asking that question and just showing us plate details wont give us any clues, is the impellor running free and clear of ducting (not catching and jamming)... the voltage needs to be checked when air con is on and loaded up also current demand on transformer.

And lastly what is your background so we can adapt our answers and questions to your level of knowledge.

I only have basic knowledge about motor, nothing deep. Im trying to figure out what was the problem and how can i fix it, because i asked many people who work with extractor-motor, and no one have any certain idea or solution. Im not in my country (venezuela) right now, and the people who I left running the place, i dont want them to purchased another motor and burn it again, because motor is expensive, and is illogical to play burning motor until find the right one.

The major problem was because the people who installed the system was totally irresponsible and then they dissapear. I have no idea about the extractor requirement, and no information at all in the extractor, i only have the info of the motor that was installed.

About your questions:
1.You haven't told us how you motor is connected (star or delta)?
Star
2.You haven't told us how your starting your motor?
The motor is connect directly, using pulley and strap. ( thats what you mean?)
3. Why are your motors burning out, where's your overload protection and what is it set at if you have?
No protection when the first motor burned out, thats why the motor was running with one phase and burned out when the electricity failure happen in the city. And then they installed a protection before installing the second motor, but still burned out.
4.Have you measured the current on each phase when the motor is running?
Im not sure, i wasnt there in that time, and the person who i left running the place have no idea or dont remember.

I know that theres lack of a lot of information, im just trying to have an idea or possible solutions, or figure out if there is any kind of solution, or if the problem is because of the electricity or because motor load or something else.

It seems like the 5hp motor with 1740 rpm is running without problem, but is not extracting air ( BIG ISSUE) but with a motor of 7.5hp and 3480 rpm burned out.
I cant neither install a to high hp motor, because of my 30kva restriction.

The thing is, what can i do to make the system extract more air without burning the motor.

Thanks a lot!
 
A make and model number for the fan would be helpful.

Why would the fan have a second motor that's completely different to the first one?

If any motor burns out due to mechanical overload or phase failure then the protection is incorrectly designed.

Why would the fan have a second motor that's completely different to the first one?
Because when i purchased the second one, wasnt available any motor with the same characteristic of the first one, and i need a motor urgently in that moment and i thought that with a higher speed motor it will extract more air and solve the problem.
 
The air conditioner is 3 phase and the other appliance like computer, refrigirator, tv, router,lamps,etc are 1 phase. Im going to try to get some pics.
Thanks
 
Pictures would be good , have had a situation when one motor was exacting and the other motor inputting in the same unit meaning that both motors were working against each other and kept tripping . This was a scratching head for a bit until the apprentice commented that they weren't wired the same way. Bit embarrassed that i didn't see it , but easy fix , dont think its helping that the motors are too different sizes,
There isnt anything jammed in the blades is there?

Jamie
 

Reply to Trouble with a 3 phase motor in the Electrician Talk | All Countries area at ElectriciansForums.net

Similar threads

Hi James, At the inverter end the multi strand is ferruled and torqued in the terminal and at the motor end they are the “wago type” push fitting...
Replies
2
Views
349
  • Question
Here are the other drawings
    • Optimistic
    • Funny
Replies
6
Views
1K

Recommended Sponsor News

Quickwire Now Sponsor ElectriciansForums.net

I am sure you will join me in welcoming our newest sponsors of ElectriciansForums.net - Quickwire! They have decided to join us after seeing you guys discussing their products here. Now we have an expert on board that you can chat to @Quickwire-Sam who will be happy to answer your queries!

[ElectriciansForums.net] Quickwire Now Sponsor ElectriciansForums.net


@Quickwire-Sam said "At Quickwire, we're all about speed, safety, and reliability. We're a family-run business, and every Quickwire connector is proudly made right here in the UK, ensuring noticeable quality. In short, Quickwire is the fastest connection method on the market. Whether you're an experienced electrician or a DIY enthusiast, Quickwire makes electrical connections ridiculously quick and easy. We're passionate about blending British craftsmanship with innovation. If you have any questions or if there's any way we can help, please just ask me!"

Exclusive Forum Offer! Free euro 2024 wall chart for first 10 responses!

Hi everyone,

We have 10 exclusive Uheat EURO 2024 Wallcharts to giveaway for Electricians Forum Members! The first 10 people to reply YES to this thread - I will message and get them sent out to you just in time for this years tournament! GO GO GO

PCBWay Now Sponsor ElectriciansForums.net!!

I hope you will all join me in welcoming our newest sponsor to the forum PCBWay! You can contact their friendly people by sending a message to @PCBWay who will be happy to answer your queries.

Welcome to the community and thanks for your sponsorship!

[ElectriciansForums.net] PCBWay Now Sponsor ElectriciansForums.net!!

PCBWay provides services including PCB Prototype and batch Production, PCB Assembly (SMT), 3D Printing, CNC Machining, PCB Design, Electronics Modules Selling, etc. We are committed to meeting the needs of global makers from different industries in terms of quality, delivery, cost-effectiveness, and any other demanding requests in electronics.

[ElectriciansForums.net] PCBWay Now Sponsor ElectriciansForums.net!!

Search Electricans Forums by Tags

OFFICIAL SPONSORS

Electrical Goods - Electrical Tools - Brand Names Electrician Courses Green Electrical Goods PCB Way Electrical Goods - Electrical Tools - Brand Names Pushfit Wire Connectors Electric Underfloor Heating Electrician Courses
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc

YOUR Unread Posts

This website was designed, optimised and is hosted by untold.media Operating under the name Untold Media since 2001.
Back
Top