Inverter problems why oh why

[cliffed]

After several asks,been told that an inverter speed controller cannot be used on a 3 phase 2 speed,4 pole motor.
All the tech guys,installers etc,couldn't tell me this at the beginning of job,but when testing the motor,it just didn't sound right,2 motors later one call I've made as finally gotten to the cause.
All the specification,was adhered to,so frustrating,what's happening out there.

 

[LeeH]

I'm having difficulty deciphering your post to be honest.

Did you have a problem with a non vsd rated motor on a vsd?

And what's a 2 speed motor?

 

[Andy-1960]

If you changed the motor why didn't you change it for a normal 4 pole motor?
I am interested in what they said and why it won't work, can you tell me more?

 

[Darkwood]

After several asks,been told that an inverter speed controller cannot be used on a 3 phase 2 speed,4 pole motor.
All the tech guys,installers etc,couldn't tell me this at the beginning of job,but when testing the motor,it just didn't sound right,2 motors later one call I've made as finally gotten to the cause.
All the specification,was adhered to,so frustrating,what's happening out there.

It's hard to make out where in this work you actually sit, are you just the end installer working to a spec and design passed down from above or are you responsible for the diagnosis, design and upgrade from concept to completion?..
If the former then indeed you are copping for the mistakes of others but if you are taking this on yourself then it is down to you to be fully knowledged in the different motor types and their suitability for VSD, manufacturers etc sell there products on the presumption you are fully aware of there suitability and limitations for any given job.
I assume been a 2 speed motor it may well be dual Kw rated and suits to different requirements of the machine, swapping out for a standard motor may not be suitable to the needs of the machine but info' is limited here.

 

[Darkwood]

I'm having difficulty deciphering your post to be honest.

Did you have a problem with a non vsd rated motor on a vsd?

And what's a 2 speed motor?

A 2 speed motor as obvious as it may sound is a motor that can run at 2 different speeds depending on which you choose through the controls, it has a wiring arrangement that allows you to choose between 2 set speeds and can in some cases look like a standard star/delta connection which for those who are dabbling in this side of the industry can have disasterous results if mistaken for the wrong kind.
You can commonly find 2 speed motors on lathes but your probably more familiar with them on cranes where you have slow and fast options for travel and/or hoist operations.

 

[LeeH]

Thank you, never come across one in my industry.

How does that work seeing as the number of poles dictate the revolutions? Seems a expensive and complicated winding arrangement.

 

[Darkwood]

Thank you, never come across one in my industry.

How does that work seeing as the number of poles dictate the revolutions? Seems a expensive and complicated winding arrangement.

I'm going to let you ponder that one for a little while but if you get stuck just click the link and read up on the Fig2 section halfway down the page .. it actually is cost effective to have a motor with 2 speeds options as oppose to all the mechanical gearing required to achieve the same thing, motors can be wound and arrange for almost any use and variation you can imagine, they are not limited to the arrangements of a standard fixed speed cage motor.
Connecting Motors for a Change Of Voltage - http://www.industrial-electronics.com/AC-DC-motors/15_Connecting-Motors-Change-Voltage.html

 

[cliffed]

I'm having difficulty deciphering your post to be honest.

Did you have a problem with a non vsd rated motor on a vsd?

And what's a 2 speed motor?

It's a bit complicated,the company I work for quoted for connecting all equipment on site,without much co operation off others.
There were several motors to connect,but the client insisted on this particular motor to have 2 speed control.
All communication with tech,motor suppliers were done by our company,I was told this & that,& now problems have arisen,with this motor being controlled by a inverter supplying variable speed control.
It's a 400 v,connected in star,& isnot compatiable with this inverter.

 

[cliffed]

If you changed the motor why didn't you change it for a normal 4 pole motor?
I am interested in what they said and why it won't work, can you tell me more?

I've not changed the motor,another company's done that,it's a 400 v motor,2 speed 4 pole motor,it's connected in star,& apparently not suited to an inverter

 

[cliffed]

A 2 speed motor as obvious as it may sound is a motor that can run at 2 different speeds depending on which you choose through the controls, it has a wiring arrangement that allows you to choose between 2 set speeds and can in some cases look like a standard star/delta connection which for those who are dabbling in this side of the industry can have disasterous results if mistaken for the wrong kind.
You can commonly find 2 speed motors on lathes but your probably more familiar with them on cranes where you have slow and fast options for travel and/or hoist operations.

Correct,2 different speeds,but some idiot advised a inverter to control this motor

 

[Darkwood]

@cliffed How many wires at the connections and how many terminals are there?

 

[cliffed]

@cliffed How many wires at the connections and how many terminals are there?

Ok there are 6 connections,L1 L2 L3,& either star or delta links.
This mother rated at 400 volts,so connected in star,links horizontal.

 

[westward10]

How do you know it is a two speed motor.

 

[cliffed]

How do you know it is a two speed motor.

It's got a high & low connection,also in its name place it's got 2/4 figure. Meaning 2 speed 4 pole.

 

[westward10]

So as it is now it is connected high speed, what is low speed no link across any of the terminals.

 

[cliffed]

Yes connection on high speed,links in star formation

 

[westward10]

Does the rating plate clearly show the different speeds and the same or different horse powers.

 

[cliffed]

Yea different rpms,amperage ,min 1.14,max 2.41 amps

 

[cliffed]

All this came to light a couple of days ago,it's just been a lack of information & communication between parties.
The guy I phoned,summed it up really,why would you put a Vsd inverter on that kind of motor,when it already is a 2 speed motor.

 

[westward10]

Stab in the dark, I suspect you have a Dahlander wound motor which is two speed and as it is connected with the link across three terminals it for high speed, this is actually star/star connected. I haven't dabbled with this for years and Darkwood can probably say whether this is correct and whether it will run from an inverter speed controller.