The 900-2800 Frame, 18 Pole, 1960kW, 6.6V, 50 Hz TEAAC Induction Motor comprises a fabricated steel motor casing employing a closed internal cooling air circuit, which is cooled using a fabricated steel air to air heat exchanger mounted above the stator housing. An internal fan is located on the rotor within the frame at the drive end for the circulation of the internal air around the windings and through the heat exchanger. An external fan is attached to the external rotor at the non drive end of the motor for the circulation of the external (cooling) air. The rotor is supported by frame mounted bearings at both ends.

The motor and cooler, together with the neutral point terminal box are designed to be purged and pressurised by a control system of the Leakage Compensation Type, using air as the protective gas from a compressed air supply. The assembly is therefore provided with an inlet for the pressurisation and purging air and external pipe work forming an air distribution system. A pressure relief, flow monitoring and spark arresting device is provided at the top of the cooler for the exit of the purging air. The enclosure low pressure monitoring port is on the side of the enclosure, on the low pressure side of the internal fan. Metal pipe work connects the port to the low pressure switch of the pressurisation and purging control system.

The main terminal box is increased safety to IECEx BAS 08.0021U. Additional increased safety terminal boxes to IECEx BAS 08.0021U are provided of the connection of the increased safety space heaters to IECEx BAS 06.0081U, current transformers, bearing and stator resistance temperature devices.

In addition, the following electrical devices form part of the motor assembly, and are certified as independent equipment:-

i) A Purge and Pressurisation Control System manufactured by Expo Technologies to IECEx SIR 07.0027X, coded Ex [px] IIC T6 (-20°C to +55°C) Gb. In addition there is an associated Expo Interface Unit to IECEx ITS 10.0003X marked Ex e IIC T5 Gb (-20°C to +55°C).

ii) Bearing Temperature Probes manufactured by Okazaki Manufacturing Company to IECEx BAS 08.0094, coded Ex de IIC T6 (-50°C to +60°C).

iii) Bently Nevada Vibration Sensors to IECEx LCI 06.0003X, coded Ex ia IIC T4 (-40°C to +100°C) Ga. Terminal facilities are provided locally for these intrinsic safety circuits, for mechanical protection purposes these are housed within a stainless steel enclosure.

The free (net) volume if the motor and cooler assembly is 20m³.

Internal earth connection facilities are provided at the main terminal box, and an external earth bonding facility is provided on the motor frame.

The motor is rated at 1960kW, 6.6kV, 3 phase, 50Hz, for S1 duty as defined in IEC 60034-1 and is for connection to a three phase supply having form and symmetry not worse than that defined in IEC 60034-1.

1. The enclosures are purged with air at a flow rate of not less than 4m3/min for a period of not less than 60 minutes.

2. Each and every machine is to be subjected to an internal overpressure test of 45mbar for two minutes, followed by a leakage test at 30mbar. The leakage shall not exceed 1.2m3/min.

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4. The pressurisation and purging system attached to the enclosures shall be subjected to a test to demonstrate effective operation under the following conditions:-

a. Underpressure - The low pressure switch shall operate if the enclosure overpressure falls below the minimum specified above (e.g. if an inspection panel is opened).

b. Purge flow failure - The purging system (including the timer) shall reset to the beginning of the purge cycle if the purging air flow rate (measured at the outlet) falls below the minimum specified above (e.g. the supply restricted during purge).

c. Supply pressure failure - The low pressure switch shall operate when or before the enclosure overpressure falls below the minimum specified above (e.g. the supply restricted after purge).

5. For correct operation the on-site pressurising air supply must be capable of providing a minimum of 0.5m3/min for leakage compensation

6. The stator winding resistance temperature devices must be automatically disconnected in the event of a purge/pressurisation failure.

7. The heating element supply circuit shall be interlocked such that the heaters cannot be energised whilst the motor is running; the supply circuit is to include a suitable overcurrent protection device as detailed in IEC 60079-7.

8. This motor is supplied with bearing insulation, the user is responsible for checking the effectiveness of such installations at appropriate intervals, e.g. by the use of a 100V insulation tester and by visual inspection to ensure that no unpainted, unearthed metal can be shorted to earth.

9. Precautions shall be taken to guard against danger from high temperature and voltage in the secondary circuit of the current transformers in the event that the secondary circuit, external to the pressurised enclosure, becomes open-circuit.

10. The attention of the user should be drawn to the need to ensure that any certified ancillaries are appropriate for the conditions of use.

11. The Conditions for Safe Use, or Schedule of Limitations as appropriate, for these certificates also apply to this motor.