Chapter hvac engineering Fundamentals: Part 1 Introduction

Electrical Features of HVAC Systems
403
Figure 12.1
Typical variable-speed drive controls.
auxilary contact types and number, pilot light requirements, and
control voltage transformer size if external devices needing control
power are involved. Figure 12.2 is a form that can be used to com-
municate such information to the electrical designer. Be sure to co-
ordinate the specification and control of two speed motors and motor
starters.
Fire and smoke detection and alarm:
The electrical designer is usu-
ally responsible for fire detection and alarm, if such is required. But
building codes require smoke detectors in the airstream of recircu-
lation fan systems larger than 2000 ft
3
/ min. If smoke is detected,
fan systems are required to shut down. Similarly, if the building
Electrical Features of HVAC Systems
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