• Gelco Electronics Private Limited

Single Phasing Preventers (SPP)

Single Phasing Preventers (SPP) for current and voltage sensing, offers protection up to motor terminals and does not allow motor to start under unfavorable supply conditions. The negative sequence current sensing is the best principle for single phasing protection. This protects motor against single phasing, high/low voltage, reverse phasing and unbalanced supply voltage condition. It can be used for any HP rated motor.

• Voltage sensing SPP: It senses negative sequence component of voltage and protects the motor against phase failure, unbalanced supply and reverse phase sequence of voltage.
• Current sensing SPP: It gives protection up to motor terminals. It senses negative sequence component of current and protects motor.
• Reverse phasing: When phase sequence is reversed, motor rotates in reverse direction. This condition is not desirable to run the motor, so the unit will trip the motor.
• Unbalanced supply current and voltage: If voltage unbalance is higher then 45+/- 5V, unit trips. If current in any two phase differs by 50% (10 A) of rated maximum current (20 A in case of 8-20 A unit) it trips motor.
• Low/high voltage cut-off: It senses supply voltage and protects the motor against too high or too low voltage conditions.
• Overload: It senses average current going to motor and protects motor against overload (over current). Overload setting is to be set at 120% of the full load current.