Page 176 - HVAC Pump Handbook

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Source: HVAC Pump Handbook

Chapter
7

Pump Drivers and

Variable-Speed Drives

7.1 Introduction
HVAC pumps are driven by electric motors, steam turbines, and gas-
or oil-fueled engines. By far most of the pumps are operated by electric
motors. Steam turbine–driven pumps are found on large central
chilled water or cogeneration plants where steam is available from
boilers or exhaust steam from turbine-driven chillers or electric gener-
ators. Engine-driven pumps are found on large pumping installations
where a source other than electricity is needed; this can be in areas of
power curtailment or where emergency pump operation is required.

7.2 Electric Motors
The following discussion makes reference to two principal organizations
in the electrical industry. These are (1) the Institute of Electrical and
Electronic Engineers (IEEE) and (2) the National Electrical
Manufacturers Association (NEMA).
Most electric motor–driven pumps in the U.S. HVAC market are single-
or three-phase, 60 Hz. Table 2.8 provides the motor nameplate voltages
and the accompanying distribution system voltages. This table provides
the best match of motor voltages to distribution voltages and meets
current motor design practice.
Although 50-Hz power is generally not used in the United States,
HVAC designers will encounter it occasionally in the United States and
when working in foreign countries. Table 2.9 also includes information
on 50-Hz power and motors. Standard pump curves are available from

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