You will need

- tester;
- - a set of wires;
- - current source with adjustable power;
- - frequency Converter.

Instruction

1

Connect the motor to a current source of variable EMF. Increase its value. Along with it will increase the voltage on the motor winding. Keep in mind that if we neglect losses in the supply conductors, which are very small, then the EMF source equal to the voltage on the windings. Calculate the magnification power of the motor. To do this, find how many times the increased tension, and lift this value into a square.

2

Example. The voltage on the windings of the motor was increased from 110 to 220 V. how many times has increased its power? The voltage increased to 220/110=2 times. Therefore, the engine power was more in 22=4 times.

3

Rewind the motor windings. The vast majority of cases, to the winding of the motor is used copper wire. Use wire of the same length, but with a greater section. The resistance of the winding will decrease and current and power of the engine at the same time increase. The voltage on the windings must remain constant.

4

Example. A motor with a winding cross-section 0.5 mm2 wound wire with a cross section of 0.75 mm2. How many times has increased its capacity if the voltage value constant? The cross section of the winding is increased 0,75/0,5=1,5 times. At the same time increased engine power.

5

When switching on three-phase asynchronous motor in single-phase domestic network, increase its useful capacity. To do this, disable one of its windings. Disappear the braking torque generated in all the windings, and the output power of the engine will increase.

6

Increase the capacity of asynchronous AC motor, increasing the frequency of the AC current flowing through the windings. To do this to the engine, attach the frequency Converter. Increasing the frequency of the applied current, increase the power of the motor. The value of the power capture by the tester operating in the mode of the power meter.

# Advice 2: How to calculate motor power

**The power**

**of the motor**, usually specified in the technical documentation or in the type plate on the case. If so it is impossible to find, calculate it yourself. This can be done by measuring the current in the windings and the voltage source. You can also determine its capacity size. Useful power is calculated by the shaft speed.

You will need

- tester;
- - table of dependence of a constant of the motor the number of poles;
- - dynamometer.

Instruction

1

Turn the motor on by connecting it to a power source with nominal voltage for which it is designed. Connect the tester in series to each winding, setting it to measure current. Find the product of the current in each winding and the voltage. The results fold. This will be the rated power of the electric motor. Voltage is measure in volts, current in amps, then get the engine power in watts.

2

To determine the power

**of the motor**without attaching it to the electric network, follow these steps: 1. A caliper measure the inner diameter of the stator core and the length in millimeters. 2. Determine the frequency of the current in the network. 3. Determine the synchronous speed of the shaft. 4. The number 3,14 multiply the diameter of the core and the synchronous frequency of the shaft. Divide the result by the number 120 and the current frequency of the network. The resulting number of pole division of the scale. 5. Find the number of poles, by multiplying the frequency by 120 and dividing the frequency of rotation of the motor shaft. 6. In the specialized table, at the intersection of the values of the pole division and the number of poles of the permanent way**of the motor**. 7. Multiply by a constant core diameter squared, length, and synchronous speed. To obtain the power in kilowatts multiply the result by 10^(-6).3

To determine the useful power

**of the motor**using a tachometer measure the rpm of shaft in Hertz (revolutions per second). A dynamometer, determine the pulling force developed in it. For this operation it is best to use a special stand. To determine the value of the net power**of the motor**, multiply the number 3,14 on the measured power, frequency of rotation of the shaft and its diameter.