BECKWITH ELECTRIC M-0245C, Instruction Book

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M-0245C High Speed Sync-Check Relay Specification

Delay after voltage change in or out of band: Generally ranges from 0 to 0.08 sec. Refer to the M-0245C
Application Guide for further details.

Maximum delay after phase change in or out of band: 1 cycle

Status Relay Contacts

Line Source Voltage OK: Contact is closed when the voltage is within the upper and lower voltage limit settings.

Phase Angle OK: Contact is closed when the phase angle between the Line and Motor Bus voltage inputs is
within the phase angle limit setting.

Analog Outputs

Phase Difference: 0 to 180° corresponding to 0 to 10 V dc (55.6 mV per degree)

Line Source Voltage: 0 to 140 V ac input corresponding to 0 to 7 V dc output

Motor Bus Source Voltage: 0 to 140 V ac input corresponding to 0 to 7 V dc output

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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.

Reliability

The M-0245C High Speed Sync-Check 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.

Transient Protection

All inputs and outputs are fully transient protected and will pass the ANSI C37.90.1-1989 Surge Withstand
Capability (SWC) Test.  The Motor Bus and Line Input Voltages, Status Relay outputs, 120 V ac Power input and
Breaker Close Circuit output will withstand 1500 V ac, 60 Hz to chassis or instrument ground for one minute.
Voltage inputs are electrically isolated from each other, from other circuits and from ground.

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NOTE: 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.

Harmonic Filters

Many applications for the M-0245C High Speed Sync-Check 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-0245C includes active filters on the bus and line voltage inputs to permit proper operation in these applications.

Environmental

Temperature Range: Units will operate properly over a temperature range of –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: Units are designed to meet extreme shock and vibration requirements.