Zeigler Current Transformer (250/5A)

This device is a professional Zeigler window type (ring type) current transformer (CT) designed for industrial electrical monitoring, protection, and metering control panels.

With a transformation ratio of 250/5A, the device functions by safely scaling down high primary currents up to 250A passing through its central window down to a proportional 5A secondary output. This allows standard measurement instruments such as ammeters, energy meters, power factor regulators, and protection relays to safely monitor the main power line.

Key Features

High Accuracy Step Down Performance: Converts high current primary lines into standard 5A secondary output levels. This provides safe, precise input signals for building management systems and automation control networks.
Large Central Window Pass Through: Engineered with a contoured central aperture (window) designed to accommodate standard industrial copper busbars or heavy gauge insulated power cables.
Integrated Safety Terminal Covers: Outfitted with high visibility blue clip on protective covers over the secondary terminals. These finger safe shrouds prevent accidental contact with open circuit high voltages, protecting maintenance personnel during servicing.
Standard Circuit Markings: Explicitly stamped with international engineering notations. The primary current entry point is marked as P1 at the base, while the secondary measurement terminal connections are clearly designated as S1 and S2 to ensure precise wiring phase orientation.
Rugged Flame Retardant Casing: Enclosed inside a molded, impact resistant light grey polymer housing built to handle the mechanical and thermal stresses found in industrial switchgear rooms.

Technical Specifications

Feature	Specification
Product Type	Window Type / Ring Core Current Transformer
Brand / Manufacturer	Zeigler / Zeigler Instruments
Primary Current Rating ( $I_{pn}$ )	250 A
Secondary Current Rating ( $I_{sn}$ )	5 A
Current Transformation Ratio	250:5
Terminal Identifiers	Primary: P1 \| Secondary: S1 and S2
Rated Frequency	50 / 60 Hz networks
Insulation Voltage Class	0.72 kV continuous / 3 kV dielectric strength standard
Mounting Capability	Directly onto busbar / surface plate mount base pathways
Terminal Shroud Concept	Integrated finger safe flip covers
Compliance Approvals	CE Compliant, IEC 61869 2 standard specifications

Applications

Main Switchboard Power Metering: Installed on income busbars inside electrical distribution boards to feed current information directly into digital power multi meters and analog ammeters.
Motor Control Centers (MCC Panels): Measures running load currents on high horsepower industrial motors, giving protective relays the necessary inputs to trip circuits during overload or stalled rotor conditions.
Energy Management Systems (EMS): Provides highly accurate current telemetry data to sub metering systems to track energy consumption patterns across automated factory levels.
Control and Protection Relays: Interfaces with overcurrent, earth fault, and phase imbalance safety relays to trigger circuit breaker shunts when current exceeds safe operating limits.