Thread: VFD for 3 Phase Mini 30

Not trying to confuse any more issues here....
The cable from the VFD to the motor(s) gives off a lot of electromagnetic field 'noise'. If you intend using and electronic gear near the machine (such as digital verniers, digital readouts etc), then you really need to run that cable in metal conduit - the flexible kind if you like - and ground it at the motor end (although I don't understand why that end).
Many people find it easier or more convenient to mount the VFD on the machine with a very short shielded cable between it and the motor(s). That way the cable draping to the machine is only single phase (cheaper) and you can read the VFD display at closer range or change settings easier directly on the VFD.

On the other hand, the VFD should be installed in a dust protecting housing of some sort to keep it's fan cooled innards clean and efficiently cooled....

Your call.

Well I just rang Dave at Drives Direct. I gathered all my motor specs before I called and realized the spindle moulder motor is actually 3.1HP (2.5Kw). Dave said I would need the 5HP model which is his next size up. Unfortunately that one is UK775 which is still $927 after the 20% VAT is taken off. That's a bit over budget plus $75 freight, so $1000 all up. I think I would prefer the 240V motors and VFD for a similar price. My only problem is the pulley on the 100L motor (28mm shaft) needing to go on a 90L frame with 24mm shaft. I think I already said it is a 150mm diameter by 45 wide crowned belt pulley. Must be able to get one somewhere at a reasonable price I would think.
Graham

Originally Posted by jhovel

On the other hand, the VFD should be installed in a dust protecting housing of some sort to keep it's fan cooled innards clean and efficiently cooled....

Another approach to this is to serious beef up your dust extraction.

On my wood working lathe the VSD is mounted on a steel post about 500 mm above the lathe centre line.


Like the one on my metal work lathe I thought about putting the VSD inside a housing to protect it from dust in the end I settled for a small sheet metal roof over it to reduce the exposure to settling dust and knocks from on top. I also have 1250 cfm of air flow / dust extraction within 200 mm of the lathe centre line which is very efficient at grabbing the fine dust at source. I know this because when I measure invisible dust levels using a particle counter located right next to the VFD I only see the same levels of dust as there is present in outside shed air. Yes there is a shyte load of visible shavings on the bench and floor but the fine dust is rapidly sucked away by the 1250 cfm.

Hi Graham
Did you tell him it was 3.1hp at 440V?

Joe brings up a good point.
While I dont take much care of my cheap VSD's I do try and keep my Teco cleaner. As I am 98% steel its not nearly as much of an issue.

Big Shed, I've been meaning to add something like that over a couple of my VSD's

Stuart

Originally Posted by Stustoys

Hi Graham
Did you tell him it was 3.1hp at 440V?
Stuart

I am pretty sure he would have understood that.
The VFDs I have been quoted on by motor suppliers (WEG & TECO) were $550-650 as i think I already mentioned. The WEG guys said if I didn't get the WEG VFD my motors wouldn't be covered by warranty. Been looking at a Chinese No Name Brand VFD on EBay for $265 and you have pointed me to others overseas for under $100. Are these cheaper ones a problem, and should I worry about warranty? As for motors, the Teco won't fit because the junction box is too big. The WEGs look good but $330 each (3hp 240V 3 phase). Are Baldor a good motor? Anyone got recommendations for good motors or VFDs?
Graham

Originally Posted by gorriss

The WEG guys said if I didn't get the WEG VFD my motors wouldn't be covered by warranty.

I am almost certain that he is not telling the truth here. The motors are a complete unit in and of themselves, so it should not matter what they are driven by.
This sounds a little like Telstra not taking responsibility for their phone lines unless you use one of their telephones. I would definitely check this out with the ACCC.

Originally Posted by Bob Willson

I am almost certain that he is not telling the truth here. The motors are a complete unit in and of themselves, so it should not matter what they are driven by.

I'd ask to see this in writing on the warranty.

When I mentioned the VFD I was looking at from Shanghai Shanyu Electronics Equipment Co Ltd (link below)
2.2KW ,3HP single to 3 phase 0-600Hz Variable Speed Drive VSD VFD Motor control | eBay
they just said "never heard of it" which is understandable I guess. Obviously not all VFDs are alike and some presumably could be more likely to damage a motor than others. I guess that's why people buy reputable brands. But on the other hand, reputable brands often jack up their prices because of the brand attached. It can be hard to know!
Graham

Originally Posted by gorriss

I am pretty sure he would have understood that.

Maybe not.
Bearing in mind I am rapidly heading out of my depth.
As I understand it, "as far as the VSD is concerned" 3.1hp at 440V is 2.2kW at 415V. Running a higher Voltage higher Hp motor on a lower Voltage VSD with a lower hp rating has been discussed here in the past though I'm not award of anyone that has tired it. Though we were discussing things more along the lines of a 5kW 415V motor on a 2.2kW 240V VSD.
With a $125 VSD I'd say "give it a go". Not so sure about the $600 Teco though(without comment from someone that knows more about these things).
Also the cheaper VSDs display output current(and voltage?) so you can keep an eye on whats going on . The Teco doesnt.
In the end its your money.

I see others have covered the WEG guys.
What does WEG say about using 1 VSD on two motors?

"under $100"? under $200??

I'm not aware of anyone that has damaged a motor using a VSD(not saying it hasnt happened and my memory sucks at the best of times). I would be more worried if you were going to try run the motor at 50 and 100Hz* rather than 25 and 50Hz, but I cant really comment as I have almost never gone over 60Hz and when I have it wasnt under load(though I dont know if that matters). also while we are on the subject, if you are going to run at 25Hz watch your motor cooling.

What a wishy washy post.

Stuart

*I think Joe tested from normal 50Hz motors at higher Hz and they were running out of puff just over 100Hz if I recall correctly.

Thanks Stuart
I will give Dave another ring tonight regarding the 3.1hp @ 440V. $615 inc freight for the 3hp 240-415 model and no pulley problem to worry about (plus got my 2 speed motor still!)
Cheers
Graham

Originally Posted by Stustoys

I'm not aware of anyone that has damaged a motor using a VSD(not saying it hasnt happened and my memory sucks at the best of times). I would be more worried if you were going to try run the motor at 50 and 100Hz* rather than 25 and 50Hz, but I cant really comment as I have almost never gone over 60Hz and when I have it wasnt under load(though I dont know if that matters). also while we are on the subject, if you are going to run at 25Hz watch your motor cooling.

My Hercus 9" has 1/2HP 415V 1440 RPM running on 1.5kW 240 V SAJ VSD and I find I am changing gears because it is really only workable above 25Hz. I use it routinely at 70 Hz but have run it up to 100 Hz (2880 rpm) and it does not seem to bother it. This motor is scheduled to be swapped out for a 1 HP 1440 240V 3Ph as soon as I can get around to it.

My WW lathe has a 1 HP 415V 1440 PRM running on 1.5kW 240 V Huanyang VSD. I use it routinely at between ~25 Hz and 90 Hz with no problem. Even at 20 Hz it does not seem any warmer than at 50 Hz but I should stick a TC on it to really check this out. I have run this one up to 120 Hz but I can hear what sounds faintly like a bearing noise starting at that frequency which is why I ste the max Frequency on the VSD to 100 Hz.

Originally Posted by BobL

My Hercus 9" has 1/2HP 415V 1440 RPM running on 1.5kW 240 V SAJ VSD

My WW lathe has a 1 HP 415V 1440 PRM running on 1.5kW 240 V Huanyang VSD.

So you are running 415V motors on 240V. I presume you would lose a lot of power?

Graham

Originally Posted by gorriss

So you are running 415V motors on 240V. I presume you would lose a lot of power?

Graham

Yep, that is correct
- the original WW lathe had a 1/2 HP 240V single phase motor on it. That's why I used a 1HP 3-Phase 415V running at 240V 3 phase. It may be just my imagination but it seems to be more powerful than the original single phase motor. I suspect the 1/2 Hp motor was not even that - It's still all wired up so I will attach an ammeter and check it out.
- the Hercus 1/2 HP 415V 3Ph is being changed to a 1HP 240V 3phase so it should have a full 1HP available.

For the belt sander I am building I will use a 3HP 415V 3Ph at 240V so it will be ~equivalent to 1.5HP which is fine for a belt sander.

The problem comes when you want a full 3HP but only have 24V 3Phase, as 6HP 415V motors are pretty rare.

Originally Posted by BobL

Yep, that is correct
- the original WW lathe had a 1/2 HP 240V single phase motor on it. That's why I used a 1HP 3-Phase 415V running at 240V 3 phase. It may be just my imagination but it seems to be more powerful than the original single phase motor. I suspect the 1/2 Hp motor was not even that - It's still all wired up so I will attach an ammeter and check it out.
- the Hercus 1/2 HP 415V 3Ph is being changed to a 1HP 240V 3phase so it should have a full 1HP available.

For the belt sander I am building I will use a 3HP 415V 3Ph at 240V so it will be ~equivalent to 1.5HP which is fine for a belt sander.

The problem comes when you want a full 3HP but only have 24V 3Phase, as 6HP 415V motors are pretty rare.

So to clarify, the motors aren't dual voltage 240/415 wired in delta for 240V but are actually wired for (expecting) 415V.