Turbo pump question

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guest

Turbo pump question

Post by guest »

I got an old Pfeiffer/balzers TPU 200, but no controller. Since it's an old pump, I hope that it doesnt need much more than a motor drive inverter to run, so I would like to try and build one. The problem is I need the pinout data for the 19 pin connector on the pump.

If somebody has this data, please let me know.

With an ohm meter I found two groups of mutually connected pins, one with 5 and one with 7 pins. The 5 pin group must be the motor windings. I have spun up the pump by connecting a vacuum cleaner to the exhaust port and saw nice sinusoidal voltages at this group of pins, so I know the phase relations etc.
But for the 7 pin group I have no idea what it is. A RPM monitor? A motor phase reference? A built in vacuum gauge?

I'm not innt fusion, just playing with vacuum.
Tom Dressel
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Joined: Fri Jun 22, 2001 4:44 pm
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Re: Turbo pump question

Post by Tom Dressel »

Marko

The turbo controller is quite complex producing polyphase high frequency current with feedback control of turbo rpm. I dont think the average joe could make one up in the garage. You may be able to get the instruction manuals and schematics by calling Pfeiffer's United States office.

I have a Pfeiffer TPU-050 with controller and cable but the controller doesn't work. It has low voltage output on all phases, so I am hoping that the problem is just a power transister or something easy to fix. Yesterday, I brought it to a friend who knows a lot about repairing electronics gear.

Tom Dressel
DaveC
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Re: Turbo pump question

Post by DaveC »

The motor is probably a two or three phase permanent magnet rotor synchronous motor, which accounts for the generated voltages you saw with the vaccum cleaner spin up. (clever idea, that!)
The other leads might be temperature sensors as part of the overload protection. How many?? Some PM rotor, AC drive motors use hall effect devices for commutation signals. But if the rotor poles have a little skew, the whole system will be self starting with a lock- in as synchronous speed is reached.

Over speed protection may or may not be not needed depending on how the maximum frequency is generated.

Often, input power input is limited so the pump runs slow at high pressure, and comes up to full speed as pressures drop.

A motor drive using FETs rated for a couple amps at 50-60 V could make a simple controller. All you need to get it going is one or two phase shiftng ccts and an oscillator. Even an old LM565 VCO could drive it. The coils would effectively smooth the square wave to a reasonable sine shape. Use the LM8038 (? part number) function generator chip and you have sinewaves right out the door.

I don't know how sophisticated the controller needs to be. Probably inversely proportional to the operator's sophiciation... . You might pull it off. A 60krpm drive only requires 1KHz drive frequency for 2pole motor configuration.. ( RPM = 60*N*f , where N is number of pole pairs, and f is drive frequency),

Dave Cooper
guest

Re: Turbo pump question

Post by guest »

Thanks for the answers.

I found out that the motor has four windings connected in a kind of four-tier star - actually it's probably two center-tapped windings with the taps connected together. Phases are 0-90-180-270 degrees - actually
two windings at 90 deg.

Maybe I could drive this with a stereo audio amp plus two transformers to get things floating (because of the connected center taps)?

If a comutation phase reference is not needed, I'll try to generate the quadrature sines with some software and a PC sound card for the first try...
guest

Re: Turbo pump question

Post by guest »

You might want to check out the TEA3718 stepper motor driver IC. I believe this is used at least in the smaller Balzers controllers of that era, and will probably work on the larger with apropriate buffer XSTRs. Balzers can probably provide a manual for the matching controller for your pump, which will include the schematic.
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