Presentation by Jim Moynihan

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Fire Pump Controller Starting Methods

• Presentation byJim Moynihan
• Chicago Technical Sales, Inc.
• Application Engineering, Sales and Servicein
  Northern Illinois and Wisconsin

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ASPE Chicago Chapter Sept. 20,2007
Outline

• Fire Pump Motor Starting Methods
• What are the methods?
• Why are there different methods?
• Cost vs. Current reduction
• Motor Conductors
• Size Comparison
• Power Transfer Switches
• Recent additional circuit breaker requirement
• Questions and Answers

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Motor Starting Methods
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Motor Starting Methods
Why are different starting methods used?
To reduce the amount of current inrush (Amperage)
during motor starting.
Reducing the Amperage reduces the overall load on
the power supply system and may reduce peak usage
charges.
It also allows a smaller generator to be used
when the fire pump is operated from a generator
set emergency power source.
EXAMPLE Across the Line (Full Voltage
Starting) 125HP Motor at 460 Volts 156 FLA 156
Amps x 6 936 Amps during motor start
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Motor Starting Method Comparison
FLA Motor Full Load Amperage (See NFPA 70
Table 430.150)
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Starting Current vs. Cost ComparisonBased on
125HP at 460 volts
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Motor Starting Method ExampleBased on 125HP at
480 volts
Across the Line (Full Voltage Starting) 125HP
Motor at 460 Volts 156 FLA 156 Amps x 6 936
Amps during motor start Wye-Delta Closed 125HP
Motor at 460 volts - 156 FLA 156 Amps x 2 312
Amps during motor start
NFPA-20 Paragraph 9.4.1 States . The voltage
at the controller line terminals shall not drop
more than 15 percent below normal
(controller-rated voltage) under motor starting
conditions.
Fire Protection Engineering Note The fire pump
controller is normally specified as a component
of the fire pump system in the fire protection
portion of the specification. Coordination of
the starting method between the fire protection
engineer and the electrical engineer is required
to insure proper operation of the system.
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Motor Conductors
(3) Conductors Across the Line Primary
Resistance Autotransformer Solid State Soft
(6) Conductors Part Winding Wye-Delta
Open Wye-Delta Closed
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Motor Conductors
FLA Motor Full Load Amperage per NFPA 70 Table
430.150
Fire Protection Engineer Note One of the most
common field problems during construction is
improperly sized cables and the incorrect number
of motor cables shown on the engineering drawings.
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Size ComparisonBased on 125HP at 480 volt

• Across the Line
• Part Winding
• Wye-Delta Open
• Wye-Delta Closed
• Autotransformer
• Solid State Soft
• Primary Resistance

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Lunch and Learn
Outline

• Fire Pump Motor Starting Methods
• What are the methods?
• Why are there different methods?
• Cost vs. Current reduction
• Motor Conductors
• Size Comparison
• Power Transfer Switches
• Recent additional circuit breaker requirement
• Questions and Answers

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Wisconsin Fire Protection SymposiumSeptember 18,
2007

• Power Transfer Switches
• Alternate Source Circuit Breaker

NFPA-20 2007 10.8.2.1.5 Where the alternate
source is supplied by a generator whose capacity
exceeds 225 percent of the fire pump motors rated
full-load current, the controller shall be
equipped with the alternate side circuit breaker
and isolating switch in accordance with 10.8.2.1.
(10.8.2.1 specifies a circuit breaker with the
same characteristics as the circuit breaker for
the normal utility power source)
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Wisconsin Fire Protection SymposiumSeptember 18,
2007

• Power Transfer Switches
• Alternate Source Circuit Breaker

Example 150HP fire pump motor at 460 voltswith
500KW generator. 150HP motor at 460 volts 180
amps 500KW Generator at 460 volts 750
Amps 180 amps (motor) x 225 405
Amps Therefore the generator capacity (750 Amps)
exceeds 225 of the motor full load amperage (405
Amps) and an alternate side circuit breaker must
be specified.
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QUESTIONS?
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• Thank You for Attending!