Peat electrical installations. Electric motors, switching devices

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ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING
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Section 7. Electrical equipment of special installations

Peat electrical installations. Electric motors, switching devices

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

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7.7.32. Switching devices of electric motors above 1 kV should be placed in metal cabinets.

7.7.33. Switching devices of electric motors above 1 kV must have a lock that does not allow:

disengagement of the disconnector under load;
switching on the disconnector when the starting device is on;
opening the cabinet with the disconnector switched on;
switching on the disconnector with the cabinet open.

7.7.34. Disconnectors must be installed in front of switches and fuses above 1 kV.

If there are detachable contact connections, through which the cable supplying the installation with electricity is connected to the overhead line, the installation of an additional disconnector is optional.

In the case of the use of clip-on terminals, it is necessary to install an additional disconnector in front of the transformer on the power supply side, as well as in front of the device with a voltage transformer.

7.7.35. It is allowed to start an electric motor connected to a separate transformer using a starting device installed on the higher voltage side of the transformer, without installing switching devices between the electric motor and the transformer.

7.7.36. On switching devices of electric motors above 1 kV, the installation of voltmeters and ammeters is mandatory. When installing several electric motors above 1 kV on one unit, one voltmeter is provided for the entire group of electric motors.

7.7.37. The cross section of the cable connecting the switching device with the electric motor is selected according to the permissible continuous current; checking it for short circuit current is not required.

7.7.38. For electric motors at the moment of switching on, such a value of voltage loss is allowed, which provides the required starting torque, if this does not violate the operation mode of other electrical receivers.

Direct start of electric motors with a power not exceeding 90% of the transformer power is allowed.

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

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