AMETEK SGWC Series - Manual (Page 13)

M550129-20 REV D 1-3
effectiveness due to the lower heat capacity of the mixture; a concentration limit of 30% by
weight is recommended. No airflow for cooling is required through the unit or over the exterior of
the chassis.
1.4.1.2 INLET COOLANT TEMPERATURE
30°C, maximum operating temperature at full-rated output power; internal temperature sensors
protect against overtemperature, and will shut down individual power modules if their internal
temperature limits are exceeded; after overtemperature shutdown, the unit must be allowed to
cool down, and reset (e.g. cycling AC input power), before normal operation could be resumed.
The operating temperature of the coolant must ensure that freezing does not occur, and that the
temperature of the coolant is above the dew point in order to prevent condensation. The
minimum allowed operating temperature, 0 °C, would require the use of an ethylene/glycol
mixture to prevent freezing. Freezing could result in permanent damage to the cooling assembly
because of the resulting mechanical stresses.
Storage temperatures at 0°C and below will require an ethylene/glycol mixture to prevent
freezing. With the recommended 30% mixture (by weight), the temperature must be greater than
-15°C.
1.4.1.3 COOLANT FLOW RATE
1.25 GPM, minimum, and 2 GPM, maximum, with water coolant; water/ethylene-glycol mixtures
will require higher flow rates to compensate for the lower heat capacity of the coolant.
1.4.1.4 STATIC PRESSURE
80 PSI, maximum
1.4.1.5 STATIC PRESSURE DIFFERENTIAL
8 PSI, typical, at 1.5 GPM, inlet to outlet pressure difference with water coolant
1.4.1.6 COOLANT TEMPERATURE RISE
5.7 °C, typical, based on 87% efficiency at 15kW, and water coolant at 23°C and 1.5 GPM flow
rate
1.4.1.7 COOLANT QUALITY
The water quality should be controlled to preclude corrosion from high oxygen content,
chlorides, sulfates or bicarbonates, and excessive pH, and scaling from deposition of minerals
such as calcium or magnesium. An inlet filter is recommended to eliminate particles that could
clog coolant passages. Water with very low resistance (e.g., with high dissolved salt content) or
very high resistance (e.g., de-ionized water without corrosion inhibitor) is not allowed because of
degradation resulting from corrosion.
1.4.1.8 CONDENSATION
Internal condensation must be prevented by ensuring that the temperature of the coolant is
sufficiently high compared with the ambient air. The critical temperature is the dew point, and is
dependent on the air temperature and its relative humidity.