new england association of fire protection system designers rick dumont
TRANSCRIPT
Overview of Discussion
Two different styles of controllers are used to operate fire pumps…
Electric Controllers
Diesel Controllers
Full Voltage
° InexpensiveInexpensive
° Simple to buildSimple to build
° Standard 3 phase motorStandard 3 phase motor
• Smaller Enclosure sizes
Advantages: Disadvantages:
° Limits HP size due to Limits HP size due to inrush currentinrush current
° Generally not suitable Generally not suitable for generator usefor generator use
Reduced Voltage
° Primary ResistorPrimary Resistor° Wye Delta Open Wye Delta Open
TransitionTransition° Wye Delta Closed Wye Delta Closed
TransitionTransition
° Part WindingPart Winding° Auto-transformerAuto-transformer° Solid State Soft-Solid State Soft-
StarterStarter
Controller / Motor Type
° Across-the-lineAcross-the-line
° Primary ResistorPrimary Resistor
° Auto-transformerAuto-transformer
° Solid State Soft-StarterSolid State Soft-Starter
° Standard 3-phase Standard 3-phase induction motorinduction motor
Advantage?
•Most inexpensive motors
•Readily available
•3 wire connections from controller
Controller / Motor Type
° Across-the-line *Across-the-line *
° Primary Resistor *Primary Resistor *
° Auto-transformerAuto-transformer
° Solid State Soft-StarterSolid State Soft-Starter
° Standard 3-phase Standard 3-phase induction motorinduction motor
Disadvantage?
•Controller more expensive (*exception)
Controller / Motor Type
° Wye Delta Open Wye Delta Open TransitionTransition
° Wye Delta Closed Wye Delta Closed TransitionTransition
° Part WindingPart Winding
° Requires Wye/Delta Requires Wye/Delta motormotor
° DittoDitto
° Requires Part Wind Requires Part Wind motormotor
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 ?
° Domestic Water SystemsDomestic Water Systems° Chemical Feed SystemsChemical Feed Systems° HVAC SystemsHVAC Systems
Hardly !
How do they work ?
What does an AC Motor need to operate properly?
Rated Frequency + Rated Voltage = Rated Horsepower
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
DC Rectifiers460/3/60 Inverter0-460 vac
0-60 hz
Power Input
600 vdc
How do they work ?
Variable Frequency Drive
DC Rectifiers460/3/60 Inverter0-460 vac
0-60 hz
Power Input
600 vdc
How is pressure controlled?
Via a “Closed Loop System”
Two Components to a Closed Loop System:
How do they work ?
•Setpoint
•Feedback
Setpoint Devices…
Temperature Control Systems
How do they work ?
•Thermostat
Pressure Control Systems
•Digital Keypad
Feedback Devices…
Temperature Control Systems
How do they work ?
•Thermocouple
Pressure Control Systems
•Pressure Transducer