BECKWITH ELECTRIC M-0236B User manual

Instruction Book
M-0236B
Power Transfer Relay

Power Transfer Relay
M-0236B
SYNCROCLOSER®LINE
Ultra High–Speed Automatic Synchronizer
• For Electric Generating Plants
• For Industrial Plants
• Synchronously transfers a motor bus between alternate sources.
• Accurately closes a high-speed breaker at the first available zero phase
condition.
• Closes only if the alternate source voltage is within preset limits.

–2–
M-0236B Power Transfer Relay
Synchronous transfer of auxiliary services at a generating plant or the motor load in an industrial plant is
highly desirable to prevent either damage to critical motors or an unplanned shutdown. However, a
significant induced voltage will remain at the terminals of a rotating machine for a period of time following
removal of power. If, during the power transfer sequence, the phase angle of this voltage relative to the
auxiliary source is ignored, severe damage to an expensive machine or process may result.
The M-0236B Power Transfer Relay provides a high-speed means to synchronously close a transfer
breaker onto the disconnected but still spinning motor load, thereby avoiding damage to the machines.
The maximum phase error at the instant of breaker closing is determined by slip rate and the breaker
closing time.
Inputs
Motor Load Bus: 120 V ac nominal, 0.15 VA burden maximum.
Auxiliary Source: 120 V ac nominal, 0.15 VA burden maximum.
M-0236 Supply: 120 V ac ±10%, 12 VA burden, 50 to 400 Hz.
Optional 50 Hz operation is available.
Transfer Enable Contact: An external dry contact closure to enable the transfer sequence. This may be
an auxiliary “b” contact of the main bus breaker.
Breaker Closing Time: Programmable from 2 to 12 cycles.
■■
■■
■NOTE: All voltage inputs are isolated. The supply input and auxiliary source may be connected
together externally, provided the voltage transformer from this auxiliary supply has sufficient
capacity.
Breaker Closing Time
May be programmed by internal switches over a range of 2 to 12 cycles. The minimum time between
opening the main breaker and closing the transfer breaker is 12 cycles, assuming a 5 cycle breaker closing
time and proper phase coincidence at the end of this period.
Controls
UPPER VOLTAGE LIMIT for auxiliary voltage: 110 to 140 V ac.
LOWER VOLTAGE LIMIT for auxiliary voltage: 90 to 120 V ac.
∆∆
∆∆
∆FREQUENCY LIMIT: 0.5 to 5 Hz.
■■
■■
■NOTE: Accurately calibrated dials facilitate stable field adjustment without additional test equipment.
LED Indicators
UPPER VOLTAGE LIMIT OK: The auxiliary voltage is less than the setting of the UPPER VOLTAGE
LIMIT.
LOWER VOLTAGE LIMIT OK: The auxiliary voltage is greater than the setting of the LOWER VOLTAGE
LIMIT.
∆∆
∆∆
∆FREQUENCY LIMIT OK: The frequency difference is within the setting of the ∆∆
∆∆
∆FREQUENCY LIMIT.
READY: The unit is reset and ready. Breaker will close if the voltages and frequencies are within the preset
limits and if the Transfer Enable Contact is closed.
OUTPUT CLOSED: The solid-state output contact between TB2-A to TB2-B is closed.
TRANSFER ENABLED: The external Transfer Enable Contact is closed.

–3–
M-0236B Power Transfer Relay
Outputs
The solid-state Breaker Close Circuit is capable of controlling an inductive current of 15 A at 300 V dc. The
closing signal will remain for 0.3 seconds. Reset time is 10 seconds. Operation of the Breaker Close Circuit
is inhibited if the frequency of the auxiliary source is unstable.
The following analog outputs are provided:
∆∆
∆∆
∆Frequency: 0 to +10 V dc corresponding to 0 to 5 Hz.
Phase Difference: 0 to 10 V dc corresponding to 0 to 180° (55.6 mV per degree).
Auxiliary Source Voltage: 0 to 7 V dc corresponding to 0 to 140 V ac input .
Bus Voltage: 0 to 7 V dc corresponding to 0 to 140 V dc input .
■■
■■
■NOTE: Each analog output has an output impedance of 10 K referenced to rear terminal TB1-7. These
outputs are suitable for use with existing or future supervisory control systems.
Status Contacts
Auxiliary Source Voltage: Contact is closed when the voltage is within the UPPER and LOWER
VOLTAGE LIMIT settings.
∆∆
∆∆
∆Frequency: Contact is closed when the frequency difference between the auxiliary source and motor
bus is within the ∆∆
∆∆
∆FREQUENCY LIMIT settings.
■■
■■
■NOTE: These contacts are 20 VA dry type capable of carrying 1 A maximum, switching a 100 V dc
resistive load and withstanding 250 V dc open circuit.
Response Time
Delay after power turn on: Approx. 2 seconds. Output will be open during this period regardless of other
inputs.
Delay after closing enable input: 1/4 cycle. Output will be open until the unit is enabled regardless of
other inputs.
Delay to change in voltages in and out of band will generally range from 0 to .08 seconds.
Transient Protection
Input and output circuits are protected against system transients. The M-0236 will pass all requirements of
ANSI/IEEE C37.90.1-1989 defining oscillatory surge withstand capability. All inputs and outputs will
withstand 1500 V ac to chassis or instrument ground for one minute. Voltage inputs are electrically isolated
from each other, from other circuits, and from ground. Use of varistor suppressors across contacts and
from contacts to chassis ground is suggested if these contacts are to be tied to long wire runs.
Reliability
The M-0236 Power Transfer Relay is assembled on a single glass-epoxy printed circuit board, thereby
eliminating the need for plug-in connectors. All semiconductor components are hermetically sealed and of
the highest and most reliable quality available. Highly stable instrument grade capacitors and resistors are
used in critical measurement circuits to minimize the possibility of error.
Harmonic Filters
Many applications for the Power Transfer Relay will involve power systems which incorporate loads such
as variable speed drives, arc furnaces and converters which produce harmonics on the system. The
M-0236 includes active filters on the bus and line voltage inputs to permit proper operation in these
applications.

© Beckwith Electric Co.
Printed in U.S.A. (07.02.01) 800-0236B-SP-00 07/01
Variable Speed Motor Application
The M-0236B Power Transfer Relay includes a Variable Speed Motor Application circuit to facilitate proper
operation on Motor Buses utilizing commutating speed control techniques.
Environmental
Temperature Range: Stated accuracies are maintained from –40° to +80° C.
Humidity: Stated accuracies are maintained under 95% relative humidity (non-condensing).
Fungus Resistance: A conformal printed circuit board coating inhibits fungus growth.
Seismic: Unit is designed to meet extreme shock and vibration requirements.
Physical
Size: 19" wide x 3-1/2" high x 13" deep (48.3 cm x 8.9 cm x 33.0 cm). Requires two rack units space in a
standard 19" rack. May also be panel mounted horizontally or vertically.
Approximate Weight: 15 lbs (6.8 kg)
Approximate Shipping Weight: 20 lbs (9.1 kg)
Syncrocloser®Cover Kit
The M-0217 Cover Kit includes a transparent cover and mounting bracket to cover the knobs and prevent
accidental resetting.
Patents
The M-0236B Power Transfer Relay is covered by U.S. Patents 4,256,972 and 4,310,771.
Warranty
The M-0236B Power Transfer Relay is covered by a two year warranty from date of shipment.
BECKWITH ELECTRIC CO., INC.
6190 - 118th Avenue North • Largo, Florida 33773-3724 U.S.A.
PHONE [phone] • FAX [phone]
E-MAIL [email protected]
WEB PAGE www.beckwithelectric.com

WARNING
DANGEROUS VOLTAGES, capable of causing deat or serious
injury, are present on t e external terminals and inside t e equip-
ment. Use extreme caution and follow all safety rules w en an-
dling, testing or adjusting t e equipment. However, t ese internal
voltage levels are no greater t an t e voltages applied to t e exter-
nal terminals.
DANGER! HIGH VOLTAGE
– This sign warns that the area is connected to a dangerous high voltage, and you
must never touch it.
PERSONNEL SAFETY PRECAUTIONS
The following general rules and other specific warnings throughout the manual must be followed during application,
test or repair of this equipment. Failure to do so will violate standards for safety in the design, manufacture, and intended
use of the product. Qualified personnel should be the only ones who operate and maintain this equipment. Beckwith
Electric Co., Inc. assumes no liability for the customer’s failure to comply with these requirements.
–This sign means that you should refer to the corresponding section of the operation
manual for important information before proceeding.
Always Ground the Equipment
To avoid possible shock hazard, the chassis must be connected to an electrical ground. When servicing
equipment in a test area, the Protective Earth Terminal must be attached to a separate ground securely
by use of a tool, since it is not grounded by external connectors.
Do NOT operate in an explosive environment
Do not operate this equipment in the presence of flammable or explosive gases or fumes. To do so would
risk a possible fire or explosion.
Keep away from live circuits
Operating personnel must not remove the cover or expose the printed circuit board while power is ap-
plied. In no case may components be replaced with power applied. In some instances, dangerous volt-
ages may exist even when power is disconnected.To avoid electrical shock, always disconnect power and
discharge circuits before working on the unit.
Exercise care during installation, operation, & maintenance procedures
The equipment described in this manual contains voltages high enough to cause serious injury or death.
Only qualified personnel should install, operate, test, and maintain this equipment. Be sure that all per-
sonnel safety procedures are carefully followed. Exercise due care when operating or servicing alone.
Do not modify equipment
Do not perform any unauthorized modifications on this instrument. Return of the unit to a Beckwith
Electric repair facility is preferred. If authorized modifications are to be attempted, be sure to follow
replacement procedures carefully to assure that safety features are maintained.

PRODUCT CAUTIONS
Before attempting any test, calibration, or maintenance procedure, personnel must be completely familiar
with the particular circuitry of this unit, and have an adequate understanding of field effect devices. If a
component is found to be defective, always follow replacement procedures carefully to that assure safety
features are maintained. Always replace components with those of equal or better quality as shown in the
Parts List of the Instruction Book.
Avoid static charge
This unit contains MOS circuitry, which can be damaged by improper test or rework procedures. Care
should be taken to avoid static charge on work surfaces and service personnel.
Use caution when measuring resistances
Any attempt to measure resistances between points on the printed circuit board, unless otherwise noted
in the Instruction Book, is likely to cause damage to the unit.

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