400hz motors, whats the deal?

willbird

Joined Nov 7, 2020
3
This is a zombie thread maybe but google brought me here :). What is really interesting is that many "inverter direct drive" washing machines use 3 phase induction motors that run around 380Hz :). They are avail for around $50 all over the place, and some cheaper VFD drives might run them just fine. We use 600Hz spindle motors at work, we can only run them 595-597 for the reasons stated earlier.
 

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MaxHeadRoom

Joined Jul 18, 2013
22,062
Most washing machines now use a electronically commutated ECM style motor, see the Fischer-Paykel site, these are outrunner motors and are direct drive, no gear-box.
ECM are used in many other applications such as HVAC fan motors etc, these often have all electronics internal to the motor..
Max.
 

willbird

Joined Nov 7, 2020
3
The one I linked up the data on looks to be an ac induction motor ? That one page is from an article or white paper that compares DC motors with ac induction motors. I’ll link the paper up later. Our 595Hz spindles at work are a little tricky to spin up. The head engineer said Allen Bradley worked with them on drive parameters when they first installed them
 

nsaspook

Joined Aug 27, 2009
7,901
Spinning up a permanent magnet poly-phase (AC servo, BLDC, etc...) motor to speed quickly requires feedback on rotor position to align the drive fields to the fixed PM motor poles or a slow ramp up to speed to allow rotor speed to match the drive frequency increases.

You can feed a BLDC three phase power and slowly ramp up the frequency to the needed speed. It will track with sufficient torque. No positional feedback or extra electronic commutation is needed.

AC induction motors don't have this problem because the shifting magnetic field pushing back for rotation is derived (induction) from the applied energy.
ALL conventional motors have alternating current through either the stators or the armature when they’re rotating. The brushed DC motor just uses mechanical commutation to generate the alternating field.
 

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strantor

Joined Oct 3, 2010
5,386
The one I linked up the data on looks to be an ac induction motor ? That one page is from an article or white paper that compares DC motors with ac induction motors. I’ll link the paper up later. Our 595Hz spindles at work are a little tricky to spin up. The head engineer said Allen Bradley worked with them on drive parameters when they first installed them
I do not know what the heck that is you linked to but it looks exactly like the series-wound/brushed/"Universal" washing motor that i have salvaged. The datasheet does not add up. It makes no sense for a high frequency induction motor OR a universal motor. They state that it has 2 poles, has a maximum frequency of 340Hz, and a maximum speed of 1800rpm. A two pole induction motor at 340Hz would be spinning nearly 20,000 RPM.

I suspect this is a universal motor. That is common for washing machines and that is what it looks like. But then why all the talk about slip and Hz? I'm puzzled.
 

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strantor

Joined Oct 3, 2010
5,386
I did some googling of the p/n and found a picture stating that it is in fact an induction motor (seems like a good bit of data to put in the DATAsheet, no?) So I'm still a bit confused about the poles. Maybe there is a misprint? It would need about 24 poles to match the max RPM at the max Hz.
 

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strantor

Joined Oct 3, 2010
5,386
Here's a video, not a particularly good one, but will at least illustrate why I first assumed it was a universal motor.


One thing that struck me was that he got 3,000 RPM out of it @ 50hz, which indicates that it actually IS a 2 pole motor. I went back to look at the datasheet and the max speed that it cites is "W.M. speed." Does that mean Washing Machine speed? If so, that's a pretty stupid datasheet. Why on earth would the maker of the motor be dictating the parameters of their customers application? The Washing Machine speed is (or should be) determined by whoever is designing the washing machine, and dependent on the drive ratio between motor pulley and drum pulley. What the washing machine designer is going to be looking for is motor shaft RPM, which is nowhere on the datasheet. What a useless waste of paper.

So I think we can assume that this motor WOULD run 20k RPM if connected to a VFD and ran up to 340Hz. That would probably make it a good spindle motor for maybe a CNC router or PCB mill.
 

shortbus

Joined Sep 30, 2009
8,208
if connected to a VFD and ran up to 340Hz.
Another big *if* would be finding a VFD that can give that Hz. Not saying they don't make them, just saying never heard of one that goes that high. I can't even imagine the problems filtering the line input reflection on one.
 

MaxHeadRoom

Joined Jul 18, 2013
22,062
The high speed spindle motor/VFD combo's operate at a max of 24000 rpm, 400 HZ two pole motor.
The motors also have a minimum RPM of 6krpm due to the low inductive reactance at anything lower than 6k.
You may have a job finding a VFD that goes over 400Hz.
Max.
 

Thread Starter

strantor

Joined Oct 3, 2010
5,386
Another big *if* would be finding a VFD that can give that Hz. Not saying they don't make them, just saying never heard of one that goes that high. I can't even imagine the problems filtering the line input reflection on one.
Most VFDs go up to 400Hz. At least most of yhe ones that I'm familiar with.
 

shortbus

Joined Sep 30, 2009
8,208
I have never seen that, that I can remember but then again the ones I use are the Chinese clone type, powered by single phase to run three phase machines in my little shop.
 

shortbus

Joined Sep 30, 2009
8,208
The popular Chinese Huanyang often used by the CNC DIY crowd also include the 400Hz 24krpm spindle as a dual deal.
Max.
I never looked into them like that, and that's the type I'm now using. I originally used on the machines Teco brand, but one by one they died. So I figured if they only last a certain amount of time, I'd just buy the Huanyang clones. Not sure but read somewhere that they are based on the Teco, and can get 2 or more of the clones for the price of one Teco.
 

MaxHeadRoom

Joined Jul 18, 2013
22,062
Just make sure you set the parameters for 6krpm minimum first! :oops:
Also the GND pin on the 4 pin, 3ph & GND spindle plug often does not have a ground conductor fitted internally, so don't relay on that for GND.
Max.
 

Thread Starter

strantor

Joined Oct 3, 2010
5,386
I never looked into them like that, and that's the type I'm now using. I originally used on the machines Teco brand, but one by one they died. So I figured if they only last a certain amount of time, I'd just buy the Huanyang clones. Not sure but read somewhere that they are based on the Teco, and can get 2 or more of the clones for the price of one Teco.
Teco is the only one I can think of that I've come across that doesn't go up to 400Hz. And maybe some oddball units like the motor+drive combinations from SEW & Lenze where there is a VFD inside the motor's weatherhead.

If you need more VFDs in the future I can recommend AutomationDirect's new GS20 drives (replacement for the old GS2). They cost the same or less than Chinese eBay drives and have all the features common to more expensive brands, including integral PLC. The software sucks at this point because like everything else they released it too early and then embark on continuous improvement with more features and bug fixes in years to come*. But as they are, they are a great deal in terms of bang for buck. I have installed several of them and no issues reported thus far.

*NOTE: they will probably become more expensive as time goes by and the software is improved and they no longer need to sell at low cost to gain acceptance.
 

Thread Starter

strantor

Joined Oct 3, 2010
5,386
It looks like Sensorless Vector control was added to the GS20 , which I believe the GS2 did not have?
Max.
I think you're correct. I do not have a lot of experience with GS2. I tend to stick with full featured drives because my installations are rarely simple like getting 3ph a lathe or mill to run on 1ph. I'm usually retrofitting purpose built production equipment and there is usually some "gotcha" which precludes the use of a simple VFD. For the more discerning customer I typically specify Yaskawa and for the cheapskate I specify AutomationDirect. I have been using GS4 but now with the GS20 I see no reason to use GS4.
 
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