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Protector trip relay - Crompton Instruments - 250 Series - AC Current with Adjustable Time Delay
Features
- Single and three-phase options
- Adjustable set point
- Adjustable time delay
- Internal differential
- LED trip indication
- Double-pole relay contacts
- Automatic reset
Benefits
- Ideal for any electrical load detection
- Over and under-current monitoring
- Suitable for electric heating systems
- Ensures load current is within generator capacity
- Detects broken drive belts on machinery
- Nuisance tripping avoidance
- Customised options
Applications
- Marine panels
- Switchgear
- Distribution systems
- Generator sets
- Control panels
- Process control
- Motor protection
- Transformers
- Overload protection
Operation
AC current protectors provide continuous surveillance of the monitored circuit. These products offer user adjustable trip point (set point) and time delay settings. The set point adjustment range is between 40% and 120% of the nominal current. Input currents can be via current transformers or direct up to 10A. An internal differential setting of 1% reduces nuisance tripping if the measured signal is noisy or unstable. When the measured current moves outside the set point limit the relay will operate, giving an alarm or initiation signal. An adjustable time delay is provided to prevent the relay from tripping for a predetermined period to prevent nuisance tripping. The units draw their operating power from a separate auxiliary supply input. Single-phase and three-phase products are available. Three-phase products monitor the current level for each phase and are not phase sequence sensitive. Combined units offer under and over-current trips in one compact unit. Single function units are also available.
Over-Current Models
When the monitored current exceeds the set point, the relay will energise and the red LED will illuminate to indicate the trip condition. The relay will automatically reset once the monitored current falls below the set point minus the differential. When reset, the LED will extinguish and the relay de-energises.
Under-Current Models
When the monitored current falls below the set point, the relay will de-energise and the red LED will extinguish to indicate the trip condition. The relay will automatically reset once the monitored current rises above the set point plus the differential. When reset, the LED will illuminate and the relay energises.
Options
250 series protector relays offer various customised options to suit individual
requirements. Please consult factory.
- Adjustment ranges – different adjustment ranges are possible for the set point and differential controls.
- Relay operation – standard models are fail safe, but the relays can be customised to energise or de-energise on trip.
Product Codes
Relay Protection |
ANSI no. |
Cat. no. |
1-phase Under-current 40-120% |
37 |
252-PAU |
1-phase Over-current 40-120% |
51 |
252-PAO |
1-phase Under and over-current |
37/51 |
253-PAD |
3-phase 3- or 4-wire Under-current 40-120% |
37 |
253-PAV |
3-phase 3- or 4-wire Over-current 40-120% |
51 |
253-PAP |
Specifications
Nominal input current |
1A or 5A from CT secondary. |
0.2A to 10A available |
0.2A to 10A available on request |
Nominal frequency |
50, 60 or 400Hz |
Input current burden |
0.5VA per phase |
Overload |
2 x rating continuously, 10 x rating for 3 seconds |
Set point repeatability |
>0.5% of full span |
Differential (hysteresis) |
Pre-set at 1%. Values 1% to 10% available on request |
Trip level adjustment |
40 to 120%. Customised adjustment available |
Time delay adjustable |
0 to 10 seconds |
AC auxiliary supply voltage |
100V, 110V, 120V, 208V, 220V, 240V, 480V, ±20% |
DC auxiliary supply voltage |
12V, 24V, 48V, 110V or 125V, ±20%. Including ripple |
Auxiliary voltage burden |
4VA (max) |
Output relay |
2-pole change over |
Relay contact rating |
AC: 240V 5A, non inductive; DC: 24V 5A resistive |
Relay mechanical life |
0.2 million operations at rated loads |
Relay reset |
Automatic |
Operating temperature |
0°C to +60°C (0°C to +40°C for UL models) |
Storage temperature |
–20°C to +70°C |
Temperature co-efficient |
0.05% per °C |
Interference immunity |
Electrical stress surge withstand and nonfunction to ANSI/IEEE C37 90a |
Enclosure style |
DIN-rail with wall mounting facility |
Material |
Flame retardant polycarbonate/ABS |
Enclosure integrity |
IP50 |
Model 252 dimensions |
55mm (2.2") wide x 70mm (2.8") high x 112mm (4.4") deep |
Model 253 dimensions |
75mm (2.9") wide x 70mm (2.8") high x 112mm (4.4") deep |
Weight |
Weight Model 252: 0.4Kg approx.
Model 253: 0.6Kg approx. |
Dimensions
Model 252
Model 253
Connections
-
252-PAU
-
252-PAO
-
253-PAD
-
253-PAP
-
253-PAV
Danh mục sản phẩm
System |
Input |
Aux. Power |
Protection |
Catalog Number |
AC Current (Adjustable time delay 0-10 sec., fixed hysteresis 1%) |
Single Phase |
5A |
120V |
Under current 40-120% |
252-PAUU-LSBX-C6-DG-D1-EB |
Single Phase |
5A |
120V |
Over current 40-120% |
252-PAOU-LSBX-C6-DG-D1-EA |
Single Phase |
5A |
120V |
Under & Over current |
253-PADU-LSBX-C6-DG-D1-EC |
3 Phase 3 or 4 Wire |
5A |
120V |
Under current |
253-PAVU-LSBX-C6-DG-D1-EB |
3 Phase 3 or 4 Wire |
5A |
120V |
Over current |
253-PAPU-LSBX-C6-DG-D1-EA |