How to determine DC servo motor voltage

Ignoramus18921 · 2010-08-02T15:54:59+00:00

I have this Troyke CNC rotary table with a DC servo motor. The nameplate is missing.Thus, I do not know what is the nominal voltage of this motor. How would I measure that voltage?My own plan was, to take the motor off the rotary table, applyincreasing voltage, and watch the RPM. When RPM reaches 2,000 RPM, (orsome other speed that should be safe for any imaginable servo motor ofths kind) write down the voltage and consider it the nominal motorvoltage.This way I will probably be safe, right?Any idea how to find out max amps?i

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Gunner Asch 16 years ago

deal with it.

Indeed. Im seeing more and more OLD documents showing up on company websites. It appears that many companies are finding out that there are still a shitload of their products out there in use across the planet and it makes potential new customers feel warm and fuzzy if they find documents related to their old lines on the net.

And as you stated..it takes little or no cost to put them on the server and leave them there.

Gunner

"A conservative who doesn't believe? in God simply doesn't pray; a godless liberal wants no one to pray. A conservative who doesn't like guns doesn't buy one; a liberal gun-hater wants to disarm us all. A gay conservative has sex his own way; a gay liberal requires us all to watch and accept his perversion and have it taught to children. A conservative who is offended by a radio show changes the station; an offended liberal wants it banned, prosecuted and persecuted." Bobby XD9

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Ignoramus18921 16 years ago

deal with it.

CLausing is like this too. They even sell engineering drawings of parts that they no longer make. I will get a drawing, and make a taper attachment holding bracket.

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pyotr filipivich 16 years ago

Gunner Asch on Mon, 02 Aug 2010 16:15:12 -0700 typed in rec.crafts.metalworking the following:

deal with it.

And sometimes, you look at the old docs, realize that "Yep, it's broke for good." and go buy a new one.

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Ignoramus30076 16 years ago

I experimented some today, raising voltage, with the motor connected to the rotary table.

At 70V, the motor would spin at a 1,000 RPM, and the rotary table would go at a very reasonable speed.

Since my drives and power supply only produce 70V, I would say that I should be good with the maximum voltage that my machine is capable of and it should work well.

At this speed the motor uses about 4 amps at 70v.

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Jon Elson 16 years ago

Hmmm, that's 280 Watts. Hard to say how much is being turned into heat in the motor and how much in the worm and table, but that is a fair amount of power. I suspect you can't run it long at that speed before the motor starts really heating up.

Jon

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Ignoramus30076 16 years ago

Jon, what is guaranteed is that all power, 100% of it, is converted to heat. The table spins and does no useful work. The question is how much is dissipated in the table and how much is dissipated in the motor.

The numbers to keep in mind is amps. At lower speeds (say 20-30 volts) the motor uses 3 amps, at higher speeds (70 volts) the motor uses about 4 amps. So the amps stays about same, and what it means is that the torque and resistance losses do not change much.

I ran the motor at lower speed for 15 minutes, it warmed up, but not that much. I would say, it increased in temperature by 10 degrees or so.

I would, therefore, think that at higher speeds it would not be much different for the motor, but obviously a lot more heat goes into the table.

At any rate, this is a rotary table and is highly unlikely to see high duty cycle. This is not what rotary tables do, if I am thinking right.

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Gunner Asch 16 years ago

You are indeed quite correct. Its low cycle time.

Gunner

"A conservative who doesn't believe? in God simply doesn't pray; a godless liberal wants no one to pray. A conservative who doesn't like guns doesn't buy one; a liberal gun-hater wants to disarm us all. A gay conservative has sex his own way; a gay liberal requires us all to watch and accept his perversion and have it taught to children. A conservative who is offended by a radio show changes the station; an offended liberal wants it banned, prosecuted and persecuted." Bobby XD9

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