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Protector trip relay - Crompton Instruments - 250 Series - Frequency
Features
- Adjustable set point
- Adjustable differential
- LED trip indication
- Double-pole relay contacts
- Automatic reset
Benefits
- Over and under-frequency monitoring
- Over and under-speed monitoring
- Start standby generators
- Operation of mains failure units
- Switching standby supplies
- Protection of control gear
- Nuisance tripping avoidance
- Customised options
Applications
- Marine panels
- Switchgear
- Distribution systems
- Generator sets
- Control panels
- Process control
- Motor protection
- Transformers
- Overload protection
Operation
Frequency protectors offer user adjustable frequency trip point (set point) and differential (hysteresis) settings. The set point adjustment range is centred around the nominal 50Hz, 60Hz or 400Hz system frequency. The differential setting adjustment can be used to reduce nuisance tripping if the measured signal is noisy or unstable. When the measured frequency moves outside the set point limit, the relay will operate, giving an alarm or initiation signal. As soon as the monitored frequency moves outside of the set point limit, a trip will occur. The units draw their operating power from the measuring inputs. Combined units offer under and overfrequency trips in one compact unit. Single function units are also available.
Over-Frequency Models
When the monitored frequency 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 frequency falls below the set point minus the differential.
When reset, the LED will extinguish and the relay de-energises.
Under-Frequency Models
When the monitored frequency 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 frequency 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.
- Time delay – internal fixed time delay before a trip occurs.
- 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-frequency |
81U |
252-PHU |
1-phase |
Over-frequency |
81O |
252-PHO |
1-phase |
Under and over frequency |
81O/U |
253-PHD |
Please specify system voltage, frequency and required options at time of ordering.
Specification – Frequency
Nominal voltage |
100V, 110V, 120V, 208V, 220V, 230V, 240V, 277V, 380V, 400V, 415V, 440V or 480V
±20% |
System frequency |
40/60Hz, 50/70Hz or 360/440Hz |
Voltage burden |
3VA |
Overloads |
1.2 x rating continuously,
1.5 x rating for 10 x seconds |
Set point repeatability |
>0.5% of full span |
Differential (hysteresis) |
40/60Hz, 50/70Hz: Adjustable 0.1 to 3.0Hz
360/440Hz: Adjustable 10 to 30Hz |
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 non-function 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 |
Model 252: 0.4Kg approx.
Model 253: 0.6Kg approx. |
Dimensions
Model 252
Model 253
Connections
252-PHU
252-PHO
253-PHD
Danh mục sản phẩm
System |
Input |
Protection |
Catalog Number |
Frequency (Adjustable hysteresis 0.1-3.0Hz) |
Single Phase |
120 VAC |
Under Frequency 55-65 Hz |
252-PHUU-PQBX-C6-EB |
Single Phase |
120 VAC |
Over Frequency 55-65 Hz |
252-PHOU-PQBX-C6-EA |
Single Phase |
120 VAC |
Under & Over (2 output relays) |
253-PHDU-PQBX-C6-EC |