Download Ski 2006-Part1

New England Association
Of
Fire Protection System Designers
Rick Dumont
Evolution of Fire Pump Controllers
with
Special Emphasis on Variable
Frequency Drives
Overview of Discussion
Two different styles of controllers are
used to operate fire pumps…
Electric Controllers
Diesel Controllers
Electric Motor Driven
Diesel Engine Driven
Basic Overview
of
Electric Controllers
Full Voltage
a.k.a. - Across the Line
Reduced Voltage
Full Voltage
Advantages:
Disadvantages:
°
°
°
•
° Limits HP size due to
inrush current
° Generally not suitable
for generator use
Inexpensive
Simple to build
Standard 3 phase motor
Smaller Enclosure sizes
Reduced Voltage
° Primary Resistor
° Wye Delta Open
Transition
° Wye Delta Closed
Transition
° Part Winding
° Auto-transformer
° Solid State SoftStarter
Controller / Motor Type
°
°
°
°
Across-the-line
Primary Resistor
Auto-transformer
Solid State Soft-Starter
° Standard 3-phase
induction motor
Advantage?
•Most inexpensive motors
•Readily available
•3 wire connections from controller
Controller / Motor Type
°
°
°
°
Across-the-line *
Primary Resistor *
Auto-transformer
Solid State Soft-Starter
° Standard 3-phase
induction motor
Disadvantage?
•Controller more expensive
(*exception)
Controller / Motor Type
° Wye Delta Open
Transition
° Wye Delta Closed
Transition
° Part Winding
° Requires Wye/Delta
motor
° Ditto
° Requires Part Wind
motor
Disadvantage?
•Motor may be a long lead item
Purpose of any electric Fire Pump
Controller…
…to start a motor, without jeopardizing the
power source, and bring it to it’s fully rated
horsepower
Only then will a pump
provide rated pressure and
flow to satisfy the design
requirements.
Would it be beneficial to you as
designers and installers…
…if you could limit the pressure of the
system by changing the speed of the
pump?
A Variable Frequency Controller…
…can “vary” the speed of a motor to “maintain”
a desired pressure in a system.
Rocket Science ?
Hardly !
° Domestic Water Systems
° Chemical Feed Systems
° HVAC Systems
How do they work ?
What does an AC Motor need to
operate properly?
Rated Frequency + Rated Voltage = Rated Horsepower
How do they work ?
Three phase AC power
2 Components
•Frequency
•Amplitude
How do they work ?
A traditional reduced voltage controller…
…changes voltage level only
…reduces inrush current
…frequency is constant
How do they work ?
Variable Frequency Drive
Also known as…
•Variable Speed Drive
•Inverter
•VFD or VSD
How do they work ?
Variable Frequency Drive
Power Input
460/3/60
DC Rectifiers
Inverter
600 vdc
0-460 vac
0-60 hz
How do they work ?
Variable Frequency Drive
Power Input
460/3/60
DC Rectifiers
Inverter
600 vdc
0-460 vac
0-60 hz
How do they work ?
How is pressure controlled?
Via a “Closed Loop System”
Two Components to a Closed Loop System:
•Setpoint
•Feedback
How do they work ?
Setpoint Devices…
Temperature Control Systems
•Thermostat
Pressure Control Systems
•Digital Keypad
How do they work ?
Feedback Devices…
Temperature Control Systems
•Thermocouple
Pressure Control Systems
•Pressure Transducer
How do they work ?
Setpoint Device