1.8 Temperature control system
1.8.1 HCDP pump temperature control system
The headplate and the fourth stage of the HCDP pump have a direct cooling system in which
water flows around these parts of the pump. All other stages of the pump are air-cooled by
natural convection and radiation.
The pump-motor is cooled by water which flows through a cooling jacket which surrounds
the motor. The cooling-water supply and return pipelines are connected to the iH system by
connectors at one end of the iH system (Figure 1-5, items 2 and 3).
The cooling-water manifolds on the pump distribute the cooling-water to the pump cooling
circuit and to the pump-motor cooling circuit (and to the HCMB pump-motor cooling circuit,
on an iH600, and iH1000 system). The manifold on the pump headplate also houses a control
plug and a blanking plug, which are used to configure the cooling water system for optimal
operating temperature. (See Section 3.5)
A surface temperature sensor (Figure 1-6, item 11) is fitted to the pump-body to measure the
temperature of the pump-body. The output of the thermocouple is monitored by the iH
control system: see Section 1.10.3.
For safety reasons, a shut down thermistor is fitted to the pump headplate manifold block. The
thermistor is a solid state device, which has a resistance that changes with temperature. The
thermistor is connected to the iH control system and is used to provide warning of cooling
system failure. It is also connected to the relay interlock circuit and will cause the iH system to be
shut down if the temperature exceeds 60° C.
A motor - protection thermistor is fitted to the pump-motor. This thermistor is a solid-state
device which has an electrical resistance of less than 750 W at normal pump-motor operational
temperature. If the pump-motor is too hot, the electrical resistance rises quickly to 4000 W or
more. The thermistor is connected to the relay interlock circuit and will cause the system to be
shut down if the pump-motor is too hot.
A water flow-switch is fitted in the pump-motor water manifold. The output of the flow-switch
is monitored by the iH control system and provides an indication of low water flow through the
pump.
1-8 iH Dry Pumping Systems
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