Section 1 General Rules

Norms of acceptance tests. DC machines

Encyclopedia of radio electronics and electrical engineering / Rules for the installation of electrical installations (PUE)

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1.8.14. DC machines with power up to 200 kW, voltage up to 440 V should be tested according to paragraphs 1, 2, 4c, 8; all the rest - additionally according to paragraphs 3, 4a, 5 of this paragraph.

Exciters of synchronous generators and compensators should be tested according to paragraphs 1-6, 8 of this paragraph.

The measurement according to clause 7 of this paragraph should be made for machines that arrived at the installation site in disassembled form.

1. Determination of the possibility of switching on without drying DC machines.

Should be produced in accordance with the manufacturer's instructions.

2. Measurement of insulation resistance.

a) Winding insulation resistance.

The measurement is carried out at a nominal winding voltage of up to 0,5 kV inclusive with a megohmmeter at a voltage of 500 V, and at a nominal winding voltage above 0,5 kV - with a megohmmeter for 1000 V.

The measured value of insulation resistance must not be less than that given in Table 1.8.7.

b) Insulation resistance of bandages.

The measurement is made relative to the housing and the windings held by them.

The measured value of the insulation resistance must be at least 0,5 Mohm.

3. Insulation test with increased voltage of industrial frequency.

The test is carried out according to the standards given in Table 1.8.8. The duration of application of the normalized test voltage is 1 min. Windings of machines with a power of less than 3 kW may not be tested.

4. DC resistance measurement:

a) excitation windings. The resistance value should differ from the manufacturer's data by no more than 2%;

b) armature windings (between collector plates). The resistance values ​​​​should differ from one another by no more than 10%, except in cases where the fluctuations are due to the winding connection scheme;

c) rheostats and ballast resistors. The total resistance is measured, the integrity of the taps is checked. The resistance values ​​should differ from the manufacturer's data by no more than 10%.

5. Removal of characteristics of idling and testing of coil insulation.

The voltage rise should be made: for DC generators up to 130% of the rated voltage; for exciters - up to the highest (ceiling) or factory-set voltage. When testing the coil insulation of machines with more than four poles, the average voltage between adjacent collector plates should not exceed 24 V. The duration of the test of coil insulation is 3 minutes.

The deviation of the data of the obtained characteristic from the values ​​of the factory characteristic must be within the measurement error.

6. Removal of the load characteristics.

It should be made for exciters at a load up to a value not lower than the rated excitation current of the generator. Deviation from the factory specification is not standardized.

7. Measurement of air gaps between poles.

Measurements are made for machines with a power of 200 kW or more. The dimensions of the gap at diametrically opposite points should differ from one another by no more than 10% of the average gap size. For exciters of turbogenerators of 300 MW and more, this difference should not exceed 5%.

8. Test at idle and under load.

The limit of speed or voltage regulation is determined, which must correspond to the factory and design data.

Table 1.8.7. The lowest permissible values ​​of the insulation resistance of the windings of DC machines

Table 1.8.8. Power frequency test voltage for insulation of DC machines

See other articles Section Rules for the installation of electrical installations (PUE).

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