The Model PFR-1550 monitors the true power going to a motor. By sensing power (volts x amps x power factor) rather than just amps, there is much greater sensitivity. It has one adjustable trip point which can be either:
High-Relay swithces when load is above the trip point.
Low-Relay switches when load is below the trip point.
Wiring is done to un-pluggable terminal strips on the rear of the unit. Three ways to mount:
• On door or raceway – use cutout template
• Panel Mount – use template + optional Bezel Kit (No Charge)
• On wall – on standard outdoor junction box + optional Outlet Box Adapter (No Charge)
120 volts AC is taken from two of the phases. If the motor starter already has a 120-volt control transformer with 10VA of free capacity, it can be used. Otherwise, install a separate transformer. It is okay if the secondary is grounded. BE SURE TO NOTE WHICH TWO PHASES SUPPLY THE TRANSFORMER.
In 120/208V three-phase system, the 120V MUST come from a transformer connected to two of the phases. The 120V phase to ground voltage cannot be used.
The current signal is taken from the REMAINING phase. This current sample passes through the Range Finder Toroid.
It is VERY IMPORTANT that the current signal comes from the phase that IS NOT supplying the 120V control transformer. Be extra careful when the machine has reversing starters or multi-speed windings. If a wrong phase is used the control will either:
• Work backwards
• Have reduced sensitivity
If you are using a variable frequency drive, use a different control. Contact LOAD CONTROLS, INC. for help.