rewind shop

This is an example of the condition that motors are in when they are brought in. Keep in mind that not all motors are used in hospitals and many if not most are subjected to extremely hostile environments. Often motors are installed in places that everyone knows they wont last long in, but just add it to the costs of doing business because there is no way around it. If properly maintained, a motor could last many years. Bearings, Moisture, and heat are the cause of most failures.

After disassembly & inspection, the coil ends get trimmed and it is put in a large oven to burn the insullation off the wire, and also to clean all foreign material out of the stator. It will be "cooked" for approx 6 hours at 6-700 degrees. Careful attention is taken to insure that the motor is not damaged by excessive heat that could harm or destroy the core laminations, as many motors have insulation properties between the laminate plates. All the coil wire is then removed and the stator is cleaned and rechecked for any damage.

Once the stator is cleaned and has been inspected, it is coated with an insulating primer like Glyptol, and ready for the rewind bench. This is where the winder starts making the coils and makes sure they will fit properly in the extremely confined space. Insulation is installed in each of the stator winding slots to protect the wire from the metal surrounding it. The new wire used is"inverter rated" for voltage spike protection, and at AC Motor Electric they wind to the high standard of class "H" or even better. for specialty motors.

Shown here is an example of the machine that forms the coils.
After the rewinder has determined how many turnes per coil, and the exact size he needs, this tool will rotate, pulling the wire from spools (the wire is actually packaged in buckets and fed through a guide in the lid). The horsepower, voltage, turns per coil, type of wire, size of wire, number of poles are all determining factors in how each motors coils are made. Although there are many different die attachments for this, it still sometimes necessary to make a winding form for a specialty motor.

Shown here are (Left) the rolls of insulating material used to line the stator slots to protect the Magnet wire insulation. It is cut to the correct size and formed into he slots before the wire is installed. After the wire is installed, it then has an insulated cap (Right) installed to help hold the wire in place and also to help protect it further.

Here are two identical 3 phase stators from an internal gear motor. The one on the left (Gray) is all cleaned up and ready to be wound. The one on the right has been wound and has the connection leads attached. After the wire has been installed, it is bathed in a special insulation varnish, and baked at approx 250 degrees f to cure the varnish. Special attention is required here to keep all the mating surfaces clean and varnish free. Note how tightly the windings are installed and the detail given to prevent vibration from damaging them.

One winding (Left) and 2 windings (Right) burned from a single phase condition. This really shows how each of the 4 poles are arranged and wound if you look at where its burned.

These are single winding faults (turn to turn) that were probably caused from either a surge, or from an insulation breakdown caused from vibration, abrasion or contamination.

Installing the coils. The protective papers are installed and the wire is now fitted into the slots. If you have ever tried this you will know that it is quite an art. Not much spare room!.

All those Wires!!! Now they must be connected and at this point the winder decides how many leads to bring out. for example, it may need dual voltage, or star (Wye) / delta arrangements, or may just be a 3 lead motor.

Here we see the stator after the varnish tank. It has been baked and the varnish is completely hardened.
The windings are all coated, making them firm and strong so it will be able to handle any normal shock and vibration without problems.
It will be re-checked for electrical integrity before it gets the rotor and end bells installed. Also all the mating surfaces will be re-checked for alignment and cleanliness so the assembly will go well.
At this point the leads to connect it are also taken into the junction box..

Shown Below from left to right are : A surge / hy-pot high voltage tester to check the electrical insulation and integrity, An Induction Bearing heater that works like a transformer with the bearings, and a small motor balancer. Every motor will go through the necessary tests to ensure it will meet the required standards.

Shown Below is a disassembled capacitor start / capacitor run single phase motor.. The picture on the right shows the start switch mechanism on the Rotor, and the contacts in the end bell which is often a cause of failure in smaller single phase motors.

Thanks to Frank Conci Jr & Sr and Dave Conci for the insights. Hopefully this will help those who don't know...understand a little better....