Electrical Equipment in Tanzania
The electrical equipment of cranes includes current-carrying devices, electric motors, control and protection devices, heating, lighting and other electrical devices.
The power supply (current supply) of the crane is carried out using trolleys, a ring current supply and a flexible cable.
Depending on the degree of protection (its placement on the crane) from atmospheric precipitation and the category of crane placement, it is recommended to choose electrical equipment in the versions shown in Table. 1.
B8.
Electric drives of cranes operating in hot shops are made with crane motors having heat-resistant insulation.
In all crane electric drives, it is recommended to use a three-phase current with a voltage of 380 and 660 V. At the request of the customer, voltages of 220 and 500 V can be used. For the electric drive of a number of mechanisms, direct current with a voltage of 220 and 440 V can be used.
The voltage of control and automation circuits must not exceed 380 V Electrical Equipment in Tanzania AC and 440 V DC. To increase safety, control circuits usually use a voltage lower than the mains voltage.Electrical control equipment is located in cabinets or equipment cabins that protect them from mechanical damage and precipitation.
Electrical circuits for controlling the electric motors of mechanisms should exclude:
Uninsulated current-carrying parts, if their location and methods of blocking do not exclude accidental contact with them by the personnel serving the crane, must be fenced.
All parts of electrical equipment that are not included in the electrical circuits (motor cases, casings, handles of apparatus), as well as the metal structures of the crane, must be grounded. To do this, the parts to be grounded are attached to the metal structures of the crane, which must ensure the continuity of the electrical circuit.
Grounding of the moving part of the crane or cargo trolley is provided by contact through the running wheels, rollers, turntable.
Grounding of the track is carried out in accordance with the requirements of regulatory documents and the Electrical Installation Rules.
Uninsulated current-carrying parts of the electrical equipment of cranes (including switches that supply power to trolleys or to the supply cable), located in places that do not exclude the possibility of touching them, must be protected.
Apparatuses installed in lockable control rooms or in places where power is automatically removed when people enter, may not be fenced.
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