90% of total burn out of the motors are mainly due to overloading caused by unbalanced voltage conditions or phase failure. This fault remains undetected by conventional bimetallic overload relays and need a negative sequence component of voltage or current sensing single phasing preventer. They trip the motor starter if it goes beyond the set level of voltage or current.
GELCO current and voltage sensing SPP 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.
Technical Details
Single Phasing:
If any one phase is removed, the unit will trip the motor
Voltage sensing SPP:
It gives protection at sensing points only. 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 against phase failure, reverse phase sequence and unbalanced supply of the current (> 50% of rated maximum current)
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:
Unit gives protection against unbalance voltage or current. If voltage unbalance is higher then 45+/- 5V, unit trips. If current in any tow 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.
Dry run:
When motor operates without load (i.e. water pump without water), the condition is considered as dry-run. Prodless dry-run setting is to be set depending upon no-load current of the motor else it may cause the miss-tripping of the motor.
All Models protect motor against single Phasing, High/Low voltage,Reverse Phasing and Unbalanced Supply voltage condition. It can be used for any HP rated motor. Trip time delay is provided to avoid mis tripping of the motor.
Available Models
Models\Features
Unbalance Voltage
Low Volt
High volt
Reset
Remark
MINNY
45 V +/- 5V
-
-
Auto
Volatage Sensing SPP in small size
NSV-W
45 V +/- 5V
-
-
Auto
Volatage Sensing SPP in rigid construction
NSV-W1
Adjustable
(30-70V)
Cut off : 320 V +/- 5V
Cut in : 340 V +/- 5V
Cut off : 500V +/- 5V
Cut in : 470 V +/- 5V
Manual
Volatage Sensing SPP with adjustable unbalance voltage
NSV-CG
45 V +/- 5V
Cut off : 320 V +/- 5V
Cut in : 340 V +/- 5V
Cut off : 500V +/- 5V
Cut in : 470 V +/- 5V
Auto
Volatage Sensing SPP with High/Low voltage protection
NSV-CG1
45 V +/- 5V
Adjustable
(300V-380V)
Adjustable
(450V-500V)
Auto
Volatage Sensing SPP with adjustable High/Low volt
SWG
45 V +/- 5V
Cut off : 320 V +/- 5V
Cut in : 340 V +/- 5V
Cut off : 500V +/- 5V
Cut in : 470 V +/- 5V
Auto
Volatage Sensing SPP with Wate Level Guard
NSC
-
Cut off : 320 V +/- 5V
Cut in : 340 V +/- 5V
Cut off : 500V +/- 5V
Cut in : 470 V +/- 5V
Manual
Current Sensing SPP 50% of rated maximum current
NVC
45 V +/- 5V
Cut off : 320 V +/- 5V
Cut in : 340 V +/- 5V
Cut off : 500V +/- 5V
Cut in : 470 V +/- 5V
Auto
Voltage & Current Sensing SPP 50% of rated maximum
Note:SWG:SPP with water Water Level Guard(YES and NO indication provided to check the water level on the unit).
Technical Specifications
System Voltage:
415 V +/- 20%, 3, 50 Hz
Auxilliary Supply:
415V / 215 V / 110 V +/-20%,50 Hz
Output Contact Rating:
1 C/o potential free,6A resistive at 230v or
1A at 415V at 0.5 P.F.
Trip Time Delay
For single phasing, reverse phasing
Unbalance & Low/High Voltage:
4-7 secs
Recommand Wiring:
1.0 Sq. mm
Humidity:
Up to 95%RH
Enclosure:
High impact polystyrene moulded with nylon modulded connection strip
Fail safe:
Relay is energised in healthy conditions and trips in faulty conditions
Indication
NSV W :
HEALTHY
NSV CG/NSV-CG1:
ON,PHASE FAIL,L.V.,H.V
NSV W1:
POWER ON,SPP FAULTY
NSC:
SUPPLY,SPP TRIP
NVC:
CURRENT SPP HEALTHY, VOLTAGE SPP FAULTY, LOW VOLT, HIGH VOLT
