Overview

The Crompton Instruments 256‑PAS Power Relay is part of the 250 Series Protector Trip Relays, specifically engineered for reverse power protection in AC generators connected in parallel with other generators or the mains supply.

When reverse power—power flowing into the generator instead of out—exceeds a user-set threshold, the relay trips after an adjustable delay, safeguarding the generator from motoring damage.

This relay is widely applied in marine, industrial, and power generation environments where generator synchronization and protection are critical.

Technical Specifications

Key Features

• Reverse power protection: Prevents generator motoring when connected in parallel.

• Adjustable delay (0–20s): Fine-tuning avoids nuisance trips.

• User-set threshold (2–20%): Configurable to match system requirements.

• ANSI 32 compliant: Standard device code for reverse power relays.

• Compact design: DIN rail or wall mounting for easy installation.

Typical Applications

• Marine generators operating in parallel with shore power.

• Industrial power plants with multiple synchronized generators.

• Backup generator systems requiring reverse power protection.

• Process industries where generator motoring could cause costly downtime.

FAQ

Q1: What does the 256‑PAS protect against?
A1: It protects against reverse power flow into a generator, preventing motoring damage.

Q2: What is the delay range?
A2: The trip delay is adjustable from 0 to 20 seconds.

Q3: What is the setpoint range?
A3: The reverse power threshold can be set between 2% and 20%.

Q4: What are the contact ratings?
A4: Relay contacts are rated at 5A, 250 VAC / 24 VDC.

Q5: Is it ANSI compliant?
A5: Yes, it is classified as ANSI Device 32 (Reverse Power Relay).