Basler Electric BE1-51-K1E-Z1O-A0N0F / BE151K1EZ1OA0N0F Time Overcurrent Relay

BE1-87T Transformer Differential Relays provide primary protection for power

transformers and are available in either Single-Phase or Three-Phase

configurations. The solid-state BE1-87T compares the currents entering and

leaving the protected transformer. If a fault is detected, the relay initiates a trip

signal to isolate the power transformer. This limits damage to the transformer

and minimizes the impact on the power system.

BE1-87T relays use three types of restraint:

• Percentage of through-current

• Second harmonic

• Fifth harmonic

Selectivity in differential relaying is based on the ability to distinguish between

internal and external faults.

This is achieved by comparing the currents into and out of a power transformer.

Comparing these currents often requires more than two inputs.

For example:

• Power transformers may have a significant portion (greater than 10 %) of the

current flowing in a third or tertiary winding.

• Power transformers can have multiple breakers for a given winding (e.g., ring

bus or breaker and-a-half bus).

BE1-87T relays are available with up to five restraint inputs for the single-phase

unit and up to three restraint inputs per phase for the three-phase unit.

The SR8A Retrofit Voltage Regulator is an economical, direct replacement

for existing Basler Electric SR8A voltage regulators. Designed for brush

and brushless synchronous generators, it delivers precise voltage regulation,

fast response times, and dependable excitation control while fitting within

the same mounting footprint as the original SR regulator.

The retrofit package incorporates a modern AVC125-10 voltage regulator and,

where required, an internal sensing module, simplifying installation and

minimizing downtime.

Engineered for reliability in demanding power generation applications, the

SR8A Retrofit supports single- or three-phase sensing, voltage matching,

reactive droop compensation, line drop compensation, and underfrequency

protection. Its rugged design withstands harsh industrial environments,

while compatibility with accessories such as excitation limiters, power factor

controllers, and auto synchronizers makes it a versatile solution for generator

upgrades and modernization projects.

The MOC2XXX series of motor operated controls consists of a motor-driven,

variable potentiometer and the limit switches required to provide remote

adjustment of resistance or voltage. MOC2XXX controls can be specified for

ac or dc operation with 24-, 32-, 48-, or 120-volt control power.

MODEL NUMBER DEFINITION

The model number for this series of MOCs consists of the prefix MOC2

followed by three digits. The first digit establishes the input control voltage.

The second and third digits establish the output control element characteristics.

Table 1 lists the available model numbers and the corresponding operating

characteristics. For example, MOC2305 has a 32 Vdc control input and a 500

ohm, 2 watt potentiometer.The MOC2 Motor Operated Potentiometer is a

motor-driven control device

designed to provide remote adjustment of resistance or voltage in power

system and control applications.

The MOC series combines a variable potentiometer with integrated limit

switches, enabling precise remote control while ensuring dependable

operation. Available in configurations supporting AC or DC operation with

24 V, 32 V, 48 V, or 120 V control power, the MOC2 offers flexibility for a

wide range of installation requirements.

Ideal for generator control, excitation systems, and industrial power

applications, the MOC2 simplifies remote setpoint adjustment and enhances

operational convenience. Its robust design and versatile control power

options make it a reliable solution for applications requiring accurate and

repeatable voltage or resistance control from a remote location.