Overview

The Crompton Instruments 256‑PLLW Protection Relay is part of the 250 Series Protector Trip Relays. It continuously monitors real power flow in three-phase AC systems and trips when power exceeds preset limits—either too low or too high. This prevents damage to generators, motors, or connected loads due to abnormal operating conditions.

The 256‑PLLW is widely applied in marine, industrial, and power generation environments where reliable protection against under‑power or over‑power conditions is essential.

Technical Specifications

Key Features

• Dual protection: Monitors both under‑power and over‑power conditions.

• Adjustable delay (0–20s): Prevents nuisance tripping.

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

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

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

Typical Applications

• Marine generators operating in parallel with shore power.

• Industrial motors requiring protection against low or excessive load.

• Power generation plants with multiple synchronized generators.

• Process industries where abnormal power flow could cause costly downtime.

FAQ

Q1: What does the 256‑PLLW protect against?
A1: It protects against under‑power and over‑power conditions in three‑phase AC systems.

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 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 (Power Protection Relay).