[iyerks]

I have a special application for which I am looking for a solution.

There is a linear slide that is driven by hydraulic cylinder during most of the operations. However, in certain conditions, like hydraulic system failure, the user
wants to simply connect 3 phase AC supply to a motor driven linear axis which will operate the linear slide.

However, there is a limitation on size, and hence we are looking for a 80 square ( 750 watts ) or 110 square ( 1000 watts ) AC induction motor - why these sizes ? Because we ran trials with a servo motor of both these sizes.

Can we get induction motors built like servo motors ? Usually they are much larger, and hence customer is willing to look at a small power rating with a gearbox.

Ideas and suggestions wanted ASAP !

TIA

Iyer

[Dylwad]

Chinese air cooled spindle geared down might just work, diameters between 60 and 100 mm, 750 watt and up. Only issue would be the gear ratio needed since the motors typically produce the most torque at high rpm, above 18000 or so. A harmonic drive coupled to the spindle could work. Would need to be run with a vfd.

Sent from tapatalk

[Al_The_Man]

You did not mention if you want any kind of feedback control? I assume there is not at present with the HYD's?
What you need to be mindful of is whether it is possible to stall the motor at the end of the stroke, with hydraulics it does not matter.
I would look at either a DC or BLDC motor controlled by a A-M-C drive, both these are available on ebay.
The drive would give you some variable control and also has O.T. limit inputs for each stroke end.
Another alternative is a DC motor or Treadmill motor with a simple KB DC SCR drive, again you have some variable control.
You can get sophisticated VFD drives using encoder feedback that will perform close to servo performance, but IMO the former solution would be cheaper and more flexible.
Al.

[underthetire]

Might want to look at these
INTEGRAmotor BLDC Motors and Gearmotors
they have the drive built in. Nice compact package.

[iyerks]

Actually, we are not looking for servo performance - the reason why i mentioned servo is because for a given power rating, they are much smaller compared to AC induction motors. And Al, this is a situation where the system is being brought back in manual mode, they do not want any drives running it - whether servo, brushless or VFDs. They simply want to connect 415V 3 phase to the motor and use a toggle switch to rotate it.

- - - Updated - - -

Will these spindles start off if we simply connected the 220 volt 3 phase power to them ? I mean they will run at rated speed for the 50 Hz mains frequency ?

[Al_The_Man]

Can we get induction motors built like servo motors ?
Iyer

If you do not want servo like performance then I assume you mean physically built like servo's?
You could look at a smaller induction motor with a cyclo Gear box, they are physically small and high ratio.
Presumably the motors will need some reduction of some kind?
The previous comment of mine about reaching a physical limit would still apply.
Al.