If you have ever had an electric saw or other similar tool, then you probably should know how difficult it is sometimes to find and fix a malfunction. And the trouble here is not only that damage is difficult to diagnose, but the inability to buy the necessary part. That is why many home craftsmen often take risks, eliminating them independently. In this article we will tell you how to rewind an electric motor (do it yourself).
Output variables
First you will need to count the number of slats and grooves. We derive a variable K indicating the ratio of lamellas to grooves. Suppose that the former are exactly 48, while the latter are 24. Divide 48 by 24, we get the value: K = 2. Then you should find out the direction of laying, windings, their discharge, step and the first lamella.
Laying direction
The laying direction is easy to determine by simply looking at it. By the way, do not look at the extreme simplicity of this advice: if you are doing the rewinding of an electric motor with your own hands for the first time, then you can completely forget about this little thing. Imagine your feelings if at the end of the work it turns out that you have to completely redo it!
Winding pitch
The step is revealed by looking at the first upper coil. We believe that one of its sides lies in the first groove. We carefully consider how many grooves separates it from the opposite side, including this first groove in the calculation. Suppose you count six. Thus, with right-side styling, the step will be 1-6; with left-side laying (in the presence of 12 grooves) - 1-8.
First lamella offset
Having finished with this case, we will find out how much the first lamella is offset relative to the first groove. Lay the engine straight, drawing a mental line along it. Let us designate it with the letter Z. It is advisable not to rely on your memory at the same time, but carefully write down and sketch everything so that in the future there are no interesting situations. Immediately warn that rewinding electric motors at home is not an easy task, be extremely careful!
Define the first groove
To determine the first groove, you will need a special device, as well as an alternating current of 3V. How to make it, we will tell a little lower.
For left-handed installation, it will be located slightly to the right, in the groove where the last coil lies. Mark it somehow. We apply our home-made device to the place you marked, applying voltage to two adjacent lamellas. We immediately mark with a marker those on which the milliammeter value deviates somehow.
Recall that for example, we identified the value: K = 2. Thus, the device should show the deviation on two pairs of lamellas, and the marks should be on three lamellas. Otherwise, it is necessary to change the groove. If the device deviates on a larger number of pairs, then this is direct evidence of the presence of short circuits between the turns in the coils of a particular group.
Reset direction
And again, our homemade device will come in handy. Without changing the lamellas that we applied voltage to, carefully move the step to the right or left. Deviation in any of these directions also indicates a corresponding discharge.
Winding direction
Based on the direction of winding of the last coil, we determine its total value. For example, if the uppermost wire comes out of the left groove, then the winding is left-handed.
Number of turns
The number of turns is easy to find by the formula: Wk = Wn / K / 2. Here Wn is equal to the number of turns in one groove.
Homemade appliance description
As we promised, we give the assembly order of the corresponding device, which will help you rewind the electric motor. If you have at least some electrical skills, it will be quite easy to make it. To begin with, we select any suitable core, winding on it a suitable thin wire.
The width of this core should not be more than 0.2 cm, and the wall thickness - 4-5 mm. You can take for this a couple of simple scraps of a 5x40 splint, the length of which is no more than 5 cm, and between them screw a 15 mm bushing, compressing the entire structure onto a bolt. In this case, the winding is conveniently located on the frame around the aforementioned sleeve. The milliammeter, the most important part of the device, you can take from any old Soviet tape recorder. After carrying out all the above activities, we proceed to the removal of the winding from the anchor. So, where does the rewind of the electric motor begin? With your own hands you have to remove the old winding.
Removing an old winding
Most often, you will not be able to do without annealing the anchor to remove the old winding from it. Of course, before that you will need to remove the collector. The frontal part of the winding itself should be removed only after firing. This is done with a quality chisel. Carefully remove all of its residues. After removing the winding, lay the freed grooves, using for this purpose electrical cardboard.
In order to preserve it more safely, it is possible to put an electrical film under the cardboard. This is especially true in cases where asynchronous motors are rewound : they have a large load, so the insulation should be as good as possible.
Collector mounting
Starting to rewind the anchor, it is better to put the collector immediately. You should also not hesitate to solder the wire. After you install the collector, be sure to measure the insulation resistance between the shaft and the lamellas themselves. Use the aforementioned 500 V ohmmeter. Note that the resistance should not be less than 0.2 megohms.
The part of the shaft that is located between the collector and the core must be insulated with high quality. A small plastic tube with suitable dimensions is perfect for this purpose. Such tubes should be placed on the opposite side from the fan. So, how do you rewind the electric motor with your own hands?
Proceed to rewind the anchor
Having thoroughly suffered after all of the above procedures, we finally proceed to the most responsible part of our work. Rewinding of the motor armature begins !
After removing all measurements and removing the remnants of the old winding, we wind the wire onto the coils. We take a wire for rewinding electric motors with a diameter of 0.2 mm (this is an arbitrary value, it all depends on the specific model), solder it to lamella No. 1. We pass the wire into the first groove, throwing it around the shaft. From the first groove we bring the wire to the sixth (we repeat once again that everything needs to be done according to your measurements), winding the required number of turns. Solder the wire to the second lamella, forward it to the first and sixth groove. Spray the desired number of turns, solder it to the third lamella. Everything, the first group is done.
Start the second group with the third lamella. Everything is done similarly to the above procedure. If everything is done as it should, then the end of the first coil should be exactly on the first lamella. This is how the winding of the motor winding is done.
Have you laid the wire? Carefully wrap the cardboard, and to completely exclude the tearing of the coils it does not hurt to insert wedges. After that, you can fill the windings with varnish, but it is better to completely immerse them in varnish. It should be dried at a temperature of strictly 80-90 degrees Celsius (in the oven, in minimal heat). A day later, you will have a manually rewound anchor in your hands, which, if you correctly execute all of the above instructions, will work no worse than the “native” one. This is how the motor armature is rewound.