Index of Products

Master Highlights

Starting Methods

There are a variety of starting methods for Fire Pump Controllers, each with a different answer for how much current will be drawn when the motor is initially started. The more the reduction of the inrush current, the more complex the equipment must be.

The links below will discuss in detail each starting method beginning with the most basic, the Across the Line controller, or you may read a brief comparative summary here.

Across the Line
Wye Delta Closed

Part Winding
Soft Starting

Primary Reactor
Autotransformer

Wye-Delta Open
Variable Speed

Across the Line, Single Source

Inrush Current:
600%

Motor Starting Operation:
After receiving a start signal, our model MCA controller energizes the main contactor to directly connect the motor to the power source. Once connected, full voltage is applied to the motor terminals to quickly accelerate the fire pump to its normal operating speed.

Motor Starting Current:
Once connected to the line, the motor draws full locked rotor current as it accelerates through approximately 90% of full speed. Only when the speed reaches this point does the motor current begin to significantly reduce. Once past this speed, the motor current rapidly reduces to its normal running value.

Motor Starting Torque:
When energized, the motor produces its locked rotor torque to begin accelerating the fire pump. Typically as the motor acclerates, the torque produces dips slightly before it rapidly increases to the motors breakdown torque at approximately 90% of full speed. At this point the motor torque decreases as the speed increases until the motor torque produced equals the fire pump running torque requirements.

As Fire Pump Controllers can be the single highest source of power usage in a complex, this can be quite a load on the generator set. To combat this, reduced voltage starting controllers may be used.