Motion control

There are two types of induction motors which have double rotor slots. In the first type, both slots, upper and inner, are filled with the same conducting material (aluminum for example) and as a consequence the motor has a single cage finally, despite the double rotor slots. In the second type, usually different materials are to fill the upper and inner rotor slots (for example aluminum for the upper slots and copper for the inner slots). So, in this category the motor has two electrically independent rotor cages.

The only way for the two windings of any type (coils OR bars) to be electrically independent is: 1) insulate each winding with some form of groundwall, and 2) leave the ends of the windings unconnected from each other.

In the case of most double-cage windings, there is some form of electrical pathway between the upper cage material (which is in direct contact with the lamination steel) and the lower cage (which is ALSO in direct contact with the lamination steel).

Usually, the choice for a double-cage arrangement boils down to optimization of the overall cage performance between two "standard" materials available to a manufacturer: one is often a high resistance material and the other is a low resistance material. When combined, the result is a somewhat-balanced "medium" resistance material.

A servo system is a servo system and so where or how it is used, not to oversimplify, it is almost irrelevant to a controls engineer. There are a lot of questions that would have to be answered before either myself or anyone with experience in controls could give you sound advice specific to your project:

• Do you already have an EMAP Servo Press?
• Does it have a servo control system in it already?
• If it does, are you looking to integrate the Press with other automation devices?
• If it doesn't, how many axes do you need?
• Do you need a coordinated motion controller?

etc.

This is just to get you started thinking about some basic issues. I have experience with motion controls, but I am not a motion controls expert. A motion controls expert will I am sure, come up with a much more comprehensive list of questions.

As far as servos, if you are looking to learn how to program motion controls, I suggest to look into Yaskawa. Spend a few hours perusing their website. Yaskawa products have very good reputation and they have a large installed base, and, I personally like their website. It has a lot of useful information. I like Allen-Bradley as well, but you should know that I am an Allen-Bradley integrator and channel partner, and so I am somewhat partial to their products. AB stuff is expensive anyway, but for good reason. One of my colleagues for whom I have tremendous respect, with a ton of experience in motion controls is very fond of Copley.

If you Google 'Motion Controls' you'll get a ton of hits and you should find some useful info there as well.

Generally speaking, in my opinion, a big part of anything involving motion; fault handling and recovery, and of course, safety. You absolutely must take safety into consideration when dealing with motion and make it a priority.