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Some help with actuator wiring :)

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tiltawhirl

New Member
Hi all,

Been reading through the various threads but have yet to find something quite in line with my current questions. I hope someone can at least point me in the right direction. My electrical/electronics knowledge is limited to 'enough to be dangerous' but I do have a good handle on soldering and other basics of circuit design.

My question relates to taking 110ac voltage from the wall to run a 90v ac motor. Speed control is not that important, however reversing direction is a must. If it is possible to vary the speed, all the better.

What I am trying to wire is a 12" linear actuator which will be used as a lifting arm for one of my current models.

**broken link removed**

As you can see in the image, there is a black, white, and green, along with a brown and red which are spliced from the black and white that lead to the capacitors. I am assuming the brown goes onto the cap board(and has just come unsoldered) but I have no idea what to do from there.

**broken link removed**


Anyone want to give a little coaching on how to wire this thing for forward and reverse without killing myself? ;)

Thanks in advance!

tilt
 

zevon8

New Member
Hi I have seen very similar actuators to the one you have there, but they have all had DC motors. This makes reversing as simple as reversing the polarity of the motor leads. I think the one you have there is a continuous ball screw, in that when it gets to end of travel the internal lead screw can free-wheel without driving the shaft out further. You will then need some independant means of shutting off the motor once you get the travel you need. In a DC motor, reversing is done with what is called a " H-Bridge" that can be either transistors or relays.

Unless I am missing something, I don't think you have enough wires for a reverseable AC motor.
 

tiltawhirl

New Member
zevon8 said:
Hi I have seen very similar actuators to the one you have there, but they have all had DC motors. This makes reversing as simple as reversing the polarity of the motor leads. I think the one you have there is a continuous ball screw, in that when it gets to end of travel the internal lead screw can free-wheel without driving the shaft out further. You will then need some independant means of shutting off the motor once you get the travel you need. In a DC motor, reversing is done with what is called a " H-Bridge" that can be either transistors or relays.

Unless I am missing something, I don't think you have enough wires for a reverseable AC motor.


Thanks for the response. It does freewheel when it gets to the end of the screw. Perhaps a dc motor replacement is the cheapest and easiest way to go? If so, how would I go about choosing the correct dc equivalent?

thanks from a fellow Torontonian;)


tilt
 

zevon8

New Member
This may be a dumb question, but where did the 90VAC rating come from? Seems a rather odd operating voltage? As for a replacement DC motor, the package you have there is a common DC motor package for actuators, but you woould need to match the worm gear on the shaft.

Waht is it you are operating with the actuator? There may be a better way, using a different device, since my experience with that type of actuator has shown some problems. One of the draw-backs is that they are often easy to "back drive" under load, that is they will screw backwards and retract with a load if there is no mechanical braking. Acme screws will not do this.

Perhaps you have a universal type motor, and the original design used AC.
 

tiltawhirl

New Member
zevon8 said:
This may be a dumb question, but where did the 90VAC rating come from? Seems a rather odd operating voltage? As for a replacement DC motor, the package you have there is a common DC motor package for actuators, but you woould need to match the worm gear on the shaft.

Waht is it you are operating with the actuator? There may be a better way, using a different device, since my experience with that type of actuator has shown some problems. One of the draw-backs is that they are often easy to "back drive" under load, that is they will screw backwards and retract with a load if there is no mechanical braking. Acme screws will not do this.

Perhaps you have a universal type motor, and the original design used AC.


Sorry for the late reply.

MAJOR LEAGUE 'D'UH' moment on my part. it IS a 90vdc motor.:rolleyes:

So now that I know what I am dealing with, what components would I need to go from 115ac to 90vdc at around 5 amps? off the shelf supplies in Mississauga are in the $275 area which seems high to me.

Truly appreciate the help.

tilt
 

zevon8

New Member
For a linear power supply, using a transformer/rectifier/capacitors, one way to get your 90VDC would be to get what is called a "control transformer." Most have inputs wired for 240/120 with outputs for 240/120. Basically they are isolation transformers with separate windings that are coupled for 240 or 120 VAC use. You would wire the input side as though applying 240VAC, and the output as if you wanted 120VAC. Applying 120 to the 240 wired input would then give you 60VAC on the 120 volt output. The 60VAC rectified and filtered would be near 90VDC.

The reason I suggest a control transformer is that they tend to be the cheapest higher VA rated transformers.

I would try a surplus place like Active Surplus on Queen West, or maybe A1 Electronics and see if they have a suitable transformer. Control transformers usually come with screw terminals, and have the windings labelled on them.

A switching supply would be a better bet, but not sure where you could get one with that high a voltage and current output cheaply. Doing this as a linear supply is going to involve a heavy/large transformer and big caps.
 
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