Surplus motors

[Al_The_Man]

There are two methods used for sinusoidal commutation, one is by resolver (expensive) which puts out a 2ph sine wave and the third phase is produced in the control from these two to synchronize commutation.
The other is by hall type and encoder, the halls type tracks are used initially to indicate where the initial position of the poles are at power up, and once known, the encoder is used to keep track of, and synchronize the sine wave control.
If just the halls are used then this would be Brush-less DC commutation.
Al.

[walter]

Originally Posted by rpm mill This is not a endorsement of there product but the Logosol LS-131-2010 http://www.logosolinc.com/products/ls-131.htm This drive works very well with the Sanyo motors, it's a nice drive very small and lots of power (sinusoidal). So easy to hook up 3 or 4 axis just plug in the network cables. Comes with free software (LCDN) which will let you get up and running as fast as you can hook up the servo motor leads. The one big rough point is IT WILL NOT ACCEPT STEP AND DIRECTION INPUT. If anyone can find a clone to this one that will accept step and direction input please let me know.

12A continuous/ 20A peak. Would that be enough for Sanyo P5 1000w motor?

[rpm mill]

The Logosol at 12 amps continus would be very marginal and the motor would not be able to run at its max. The bigger problem with the Logosol is that you have to write the software to control motion(no step and direction input). Its possible there are applications where the P5 will work OK with a Trapezoidal drive but once again you won't be using the P5 to its potential.

[walter]

Beside the issue of step and direction. If one was to buy sinusoidal drive for 1kW motor it better be the right one... Especially if the original Sanyo drive is called "50 Amp PY2 Drive"

Just wondering...

[vmax549]

Have you looked at the LS182 series of drives. They have an 6a,8a,12a &24a models plus they take step and direction. An added feature is they run on DCv for us that already have power supplies. Now all we need is prices. Anyone a dealer out there that might could work a deal? TP

[DerekZahn]

The 8/12 amp one looks like about $400:

http://clickautomation.com/products/...c=list&cid=172

Does the LS-182 do sinusoidal commutation? I get the impression from that web page that it does not.

[Xerxes]

I measured the waveform of the Sanyo motor with an oscilloscope (the first picture). It looks almost like sine but not exactly. Anyway I think it's meant to be sinewave type motor (far from trapezoid or rectangular). Edit: this motor is the 300W model.

There is also captured waveform of another servo motor (the second pic).

[miljnor]

correct me if I am wrong but all motors will output a sine wave. I don't believe there is such a thing as a digital motor.

You can comutate a motor either way weather it was ment to or not it just might not run smoothly if you do it with a trapazoidal wave do to coging(probably do to Low number count).

The trapazoidal drive is still a sine wave but it is a trapazoidal sine wave. It looks like stair steps. Personaly I think the trapazoid has more of a chance working properly on a sine wave motor that the opposite. If the PWM of the trapazoidal wave is fast enough the wave will end up looking rather conventional sign wavish (any hear take integral calc?). But a sinusoidal wave is smooth but slow reacting at low rotor speeds so if the motor is under load it would seem to me that the phase shift would cause problems.

I read an artical on both styles of commutation and the artical was saying that if you want low speed power use trapazoidal if you want High speed power use sinusoidal.

So my question to the guys in the Know: why is everyone saying that trapazoidal commutation will have problems with low rpm? (being since this is its purpose in life)

please don't answer unless you "know" if its a guess please tell me you making a guess. I personaly think these motors will work fine either way. I don't have time in the next few weeks/months to try the rutex but when I get around to it I think it will work.

[Xerxes]

Originally Posted by miljnor correct me if I am wrong but all motors will output a sine wave. I don't believe there is such a thing as a digital motor. ... But a sinusoidal wave is smooth but slow reacting at low rotor speeds so if the motor is under load it would seem to me that the phase shift would cause problems. I read an artical on both styles of commutation and the artical was saying that if you want low speed power use trapazoidal if you want High speed power use sinusoidal.

Trapezoidal motor is differently wound compared to sinusoid motor. If you turn motor shaft it will generate a voltage waveform that shows its optimal commutation sequence.

I think sinusoidal drive can be superior in every way. A good sine drive will measure current phase shift and compensate it. If trapezoid would be optimal in some speed range then it would be possible to build a drive that swithes to trapezoidal drive when its optimal.

Do you have the links to those articles you read? It would be interesting to see what kind of drives they were talking about to be able to avoid same mistakes

[rpm mill]

I posted the link so let me set the record straight. The good Logosol is the Sinusoidal Drive (LS-131-2010). It's a networked drive and you can easily set up may axis and they all use the same network cable. We need to encourage other manufactures to think along this line. The LS 182 is step and direction but it is a Trapezoidal drive. Price for the LS182Hx-3005 (30Amp peak, 24Amp continues, 18 to 50 Volt input----$639.00----. Price for the LS182x-2010 (20Amp peak, 12Amp continues, up to 90 volt input-----$450.00

[DerekZahn]

The 400w motors and the 300w-no-brake motors are sold out.

[miljnor]

Sorry Xerxes I surf the net all the time just reading random not necessarily related stuff because I am a bookworm! So I don't remember the link. But I will Look tonight and see if I can find the article but just from past experience, If you don't book mark it you probably wont find it again.

Like I have posted earlier I am not an electronics guy so the article in question and info on the net is the only thing I have ever read on the brushless motor subject so It wouldn't surprise me If my info is erroneous! Was not looking to start anything just spewing what was read. you know how it is, GIGO Garbage in, Garbage out!