Beckwith Electric M-0115A Parallel Balancing Module

Provides all components that are required for paralleling LTC Transformers

using the Circulating Current Method

The M‑0115A Parallel Balancing Module includes all the components that

must be added to load tapchanging (LTC) transformers to permit them to

operate in parallel, using the circulating current method. The transformer

controls must have a 0.2 A input for load and circulating current. Through

the use of a circulating current sensitivity adjustment, the M‑0115A avoids

the problems of hunting (caused by too much sensitivity), or permitting

the transformers to be several steps apart (caused by too little sensitivity).

The M‑0115A conforms to the procedure described in ANSI C57.12.10‑1988.

paragraph 10.2.

Current Inputs

Rated at 0.2 A, 12 VA, 50/60 Hz.

Current Ratings

Either winding K1. K2 or ACT from terminal TB1‑1 to TB1‑5 is rated for 0.2 A

continuous.

All windings will withstand the following: 0.4 A continuous, 2.9 A for 5 sec;

3.3 A for 4 sec; 4.0 A for 3 sec;

5.0 A for 2 sec.

Cores are unsaturated at 12 VA burden.

Sensitivity Control

Sensitivity adjustment prevents LTC transformers from hunting or being several

steps apart.

Sensitivity is adjustable from two times normal to 0.5 times normal in nine steps.

Parallel/Independent Switch

Mode of LTC control is switch selectable.

Transient Protection

Input and output circuits are protected against system transients. The M‑0115A

will exhibit no component failure or false commands when subjected to the

requirements of ANSI/IEEE C37.90.1-1989. which defines oscillatory and fast

transient surge withstand capability. All inputs and outputs will withstand 1500

Vac to chassis or instrument ground for one minute. Voltage inputs are electrically

isolated from each other, from other circuits, and from ground.

Mounting

Panel mounted using 8‑1/2" x 6‑1/8" cutout (21.59 cm x 15.56 cm). May be

surface mounted using the M‑0124 Surface Mounting Adapter.

Environmental

Temperature Range: Stated accuracies are maintained from ‑40° to +80° C.

Humidity: Stated accuracies are maintained at up to 95% relative humidity

(non‑condensing).

Fungus Resistance: A conformal printed circuit board coating inhibits fungus

growth.

Terminal Block Connections/Torque Requirements

The M‑0115A Parallel Balancing Module is listed to UL Standards for Safety by

Underwriters Laboratories Inc. (UL). The wire should be No. 22–16 AWG inserted

in an AMP #36157 (or equivalent) connector, and the screws tightened to 4.8

inch‑pounds torque.

Physical

Size: 10" high x 6 3/8" wide x 4 15/32" deep (25.40 cm x 16.19 cm x 11.35 cm).

When using the M‑0124 Surface Mounting Adapter, maximum depth is 4 9/16"

(11.59 cm).

Approximate Weight: 6 lb (2.7 kg).

Approximate Shipping Weight: 7 1/2 lb (3.4 kg).

Warranty

The M-0115A unit is covered by a five year warranty from time of purchase.

Application

This manual includes an overview of typical system setup and connections, necessary

components, and the information necessary to implement a paralleling scheme using

the M‑0115A in the Circulating Current paralleling method.

Using the M‑0115A with Existing Equipment

The M‑0115A Parallel Balancing Module can be ordered with new equipment from

most transformer manufacturers or added to existing transformers. If the Module is

added to existing equipment, the following factors should be considered:

• If the old control uses a 5 A input for the line drop compensator, a new control must

be installed to provide the required 0.2 A load and circulating current inputs.

A Beckwith Electric M‑2001C/D Tapchanger Control is recommended for this application.

• The M‑0115A is designed for use with 200 mA = 1 P.U. system currents. If only 5 A

currents are available, then a suitable 5 A:0.2 A Auxiliary Current Transformer, such as

the Beckwith Electric M‑0169A, is recommended.

• If phase‑to‑phase voltage is used, two current transformers are used to derive a

current in phase with the voltage. Connection must be made to Terminal 5 of the M‑0169A

instead of Terminal 1.

Only required with M‑0067E, M‑2001C/D have a Phase Angle Correction Setting for this