schematic needed; five phase stepper controller

Google "5 OR five wire stepper"

Control them via PC ... how? Serial port? Parallel port? USB? Bluetooth?

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Rich Webb     Norfolk, VA

I have googled but not with much success :S.. via Parallel port @ win98 :)

Google "stepper parallel"

The second entry is

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Rich Webb     Norfolk, VA

I see that you are not familliar with this kind of stepper motor. It cannot be driven with bipolar driver and it can be driven with regular home made stepper controllers.. This kind of stepper has 5 wires and 5 coils.. all of them are connected to pentagon.. so it is different than others, 4 coil steppers..

Ivan schrieb: ...

Perhaps you can find something helpful here:

Ciao

Reinhard

Sorry but no.. i can't find anything that is useful for me.. i want to build two 5 phase controllers, not buy them..

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These motors are pretty rare. Only reference I have is this...

Personally, for the amount of bits involved I simply wouldn't bother. The normal 2 coils motors are much better served.

ive phase (five wire, penta

99% of applications, regular 2 phase steppers are every bit as good. But, the 5 phase units do, for reasons I do not understand, run at ~ 10X lower velocity ripple when run at equivalent microstep ratio. They cost too much, they do not have multiple sources, they require non- standard drive electronics.... but, boy, do they run smooth!

W Letendre

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five phase (five wire, penta

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Very probably you can make the motor run by feeding the wires with five sinusoidal currents, the five phases being equally distributed in phase. (72 degrees of phase between adjacent phases)

You can identify the phase relationship between the wires by attaching them to an oscilloscope whilst rotating the shaft of the motor. If there is no centre-tap terminal to connect to ground during this experiment then you can connect a resistor (e.g. 1k) from each terminal to the oscilloscope ground so that mains hum does not complicate your results.

You could make the sinusoidally controlled current sources either using linear circuitry (e.g. op-amp and power transistor) or using switched-mode circuitry. Linear circuitry would probably be easier to design, but switched-mode circuits would allow less power to be wasted as heat, and may permit you to obtain better performance from the motor given a limited amount of power from your power supply.

If there is a centre tap then you could tie that to some voltage to prevent any of your sinusoidal current sources from saturating, otherwise you could sense the average terminal voltage by connecting say 100k resistors in a star configuration from each wire of the motor to an artificial centre-tap voltage sensing node, and then use an opamp to slightly adjust the current into one or more of the motor wires so that the artificial centre-tap that senses the average voltage of the motor wires remains at a suitable voltage somewhere roughly in the middle of the supply rails.

To control the five currents into the wires of your motor, and since I suspect that you want smooth motion, you probably want to use DACs to generate the sinusoidal signals. You could use five DACs but it is only necessary to use two DACs, one which generates sine waves (0 degrees phase offset) and another DAC that generates cosine waves (90 degrees phase offset). In order to generate five waveforms with equally spaced phase offsets, it will be necessari to combine the outputs from the two DACs in various different proportions, for example using resistors to sum together different proportions of the two DAC outputs. In some cases, a negative amount of the DAC output must be summed, for which purpose an op-amp could be used in an inverting amplifier configuration. By using two DACs instead of five, less digital control signals will be required from the computer.

Chris