YQA Fuel Pump Motor Starters

09.01 What are the requirements for pump motor starters?

Complete protection and monitoring of pumps requires motor starter characteristics as follows:

  1. Lockable disconnect switch
  2. Hand – Off – Auto switch
  3. Motor starter / contactor
  4. Motor overload protection and monitoring contact
  5. Current sensor
  6. Design to start in Manual mode on line power – independent of control power.
09.02 What are the problems with standard submersible pump controllers?

Submersible pumps used in service stations typically have a control box that incorporates Items 3 and 4, with Item 1 covered by the circuit breaker within the building power distribution panel. These are typically not considered to be appropriate for emergency power fuel systems.

09.03 What conditions are monitored for pump motor starters?

Pump motor starters are typically monitored by the fuel system controller for the following conditions:

  • Not-in-Auto
  • Motor overload trip

Pump current

09.04 What are the benefits of VFD controllers?

Variable Frequency Drive (VFD) controllers allow for variable flow output to accommodate a range of operating conditions. The controller is set to operate with a pressure transducer input to maintain a constant pressure in the fuel supply pipe. With multiple generators, the controller automatically adjusts to the increased flow requirement when more than one day tank needs fuel.

A secondary benefit of the VFD controller is for soft start and stop of the pump to minimize fluid hammer issues in longer piping runs.