BECKWITH ELECTRIC M-0245C User manual

Instruction Book
M-0245C High Speed
Sync-Check Relay

Motor Bus Transfer Relay for
Power Plant and Industrial Site Motor Bus Transfer
• Verifies that the line voltage is within preset limits.
• Verifies within one cycle if the phase angle is within preset limits.
SYNCHRONIZING
High Speed
Sync-Check Relay
M-0245C

–2–
M-0245C High Speed Sync-Check Relay Specification
High speed 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.
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-0245C High Speed
Sync-Check Relay provides the means necessary to inhibit transfer if the phase angle is excessive or the line
voltage is out of range.
Inputs
Motor Bus Voltage: 120 V ac nominal
Line Voltage: 120 V ac nominal
M-0245C Supply: 120 V ac ±10%, 60 to 400 Hz
External Dry Contact Closure: Enables the synchronizing verification. This contact should be designed for low
voltage, low current signals.
■■
■■
■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.
Burden
Motor Bus Voltage: 0.15 VA burden
Line Voltage: 0.15 VA burden
M-0245C Supply: 12 VA burden
Controls
UPPER VOLTAGE LIMIT for Line Voltage: 110 to 140 V ac
LOWER VOLTAGE LIMIT for Line Voltage: 90 to 120 V ac
PHASE ANGLE LIMIT: Ranges are available from 0 to 180°, 0 to 120°, 0 to 60°, or 0 to 30°
■■
■■
■NOTE: Accurately calibrated dials facilitate field adjustment without additional test equipment.
LED Indicators
UPPER VOLTAGE LIMIT - OK: Line voltage is less than the upper voltage limit setting.
LOWER VOLTAGE LIMIT - OK: Line voltage is greater than the lower voltage limit setting.
PHASE ANGLE LIMIT OK: Phase difference between the Line and Bus voltage inputs is less than the phase
angle limit setting.
ENABLED: The external enable contact, rear terminal TB1-20 to TB1-21, is closed.
OUTPUT CLOSED: The solid-state output circuit, rear terminal TB2-A to TB2-B, is closed.
Breaker Close Relay
Solid-state Breaker Close Circuit is capable of making and breaking an inductive current of 15 A at 300 V dc. The
closing signal will remain until the enable contact is opened, provided phase angle and voltage remain within
preset limits.
Response Time
Delay after power turn on: Approximately 2 sec. 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 M-0245C is enabled, regardless of
other inputs.

–3–
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
■■
■■
■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.
■■
■■
■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.

BECKWITH ELECTRIC CO., INC.
6190 - 118th Avenue North • Largo, Florida 33773-3724 U.S.A.
PHONE [phone]•FAX [phone]
E-MAIL [email protected]
WEBPAGE www.beckwithelectric.com 800-0245C-00 04/01
© Beckwith Electric Co.
Printed in U.S.A. (04.24.01)
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)
The M-0245C includes a transparent cover to protect the knobs and prevent accidental resetting.
Patents
The M-0245C High Speed Sync-Check Relay is covered by U.S. Patents 4,218,625 and 4,256,972.
Warranty
The M-0245C High Speed Sync-Check Relay is covered by a two year warranty from date of shipment.
The Specification is subject to change without notice.

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.

–i–
Table of Contents
M-0245C High Speed Sync-Check Relay
Instruction Book
1.0 Introduction ................................................................................................................... 1
2.0 Theory of Operation...................................................................................................... 1
Motor Bus Undervoltage Monitor .................................................................................. 1
Input Loss Protection .................................................................................................... 1
3.0 Maintenance ................................................................................................................. 2
Figure 1 Block Diagram ............................................................................................. 3
4.0 Test Procedure ............................................................................................................. 4
Equipment Required ..................................................................................................... 4
4.1 Component Replacement Procedure ........................................................................... 4
4.2 Test Procedures ........................................................................................................... 4
Upper Voltage Limit ...................................................................................................... 4
Lower Voltage Limit ...................................................................................................... 4
Phase Angle Limit......................................................................................................... 5
Voltage Analog Output.................................................................................................. 5
Phase Angle Analog Output ......................................................................................... 5
Voltage Status Output Contact ..................................................................................... 5
Figure 2 External Connections................................................................................... 6
Phase Angle Status Output .......................................................................................... 7
Breaker Close Circuit.................................................................................................... 7
Enable Response Time ................................................................................................ 7
Phase Angle OK to Output Contact Response Time .................................................... 8
4.3 Phase Angle Detection Circuit ...................................................................................... 8
Rate of Change of Phase Angle ................................................................................... 8
4.4 Loss of Voltage Input Detection Circuits ....................................................................... 8
Line Voltage Loss ......................................................................................................... 8
Motor Bus Voltage Loss ............................................................................................... 8
Motor Bus Undervoltage Detector <25% ...................................................................... 8
Figure 3 Test Setup ................................................................................................... 9
Figure 4 Line Voltage Loss ...................................................................................... 10
Figure 5 Motor Bus Voltage Loss ............................................................................. 10
5.0 Typical Voltages ......................................................................................................... 11
Conditions................................................................................................................... 11
6.0 Typical Resistances ................................................................................................... 12
Conditions................................................................................................................... 12

–ii–
7.0 Calibration ..................................................................................................................13
Phase Angle Calibration ............................................................................................. 13
Figure 6 Component Location, B-0207 .................................................................... 14
Figure 7 Variable Speed Motor Application Option Component Location ................ 15
Figure 8 Schematic, X-0245 .................................................................................... 16
Figure 9 Variable Speed Motor Application Option Schematic, Y-0264 ................... 18
Parts List .................................................................................................................... 19
Phase Angle Limit Control Option............................................................................... 25
Parts Mounted to the Enclosure ................................................................................. 25
B-0264 Variable Speed Motor Application Option ...................................................... 26
© Beckwith Electric Co.
Printed in U.S.A. (04.24.01) 800-0245C-IB-00 04/01

–1–
1.0 Introduction
The Beckwith Electric M-0245C is a solid-state device
specifically designed to respond to changes in the
phase angle between two input voltages. When the
line voltage input is within the UPPER and LOWER
VOLTAGE LIMIT dial settings, and the phase angle
between the line voltage and the motor bus voltage is
less than that set on the PHASE ANGLE LIMIT dial,
the device will permit breaker closing. If the phase
angle exceeds the control setting, the device will
block closing within one cycle; i.e., if the limit is 30°,
the unit will inhibit closing within one cycle of the time
when the phase angle exceeds 30°. If the phase
angle returns within the 30° limit, the unit will enable
closing within one cycle.
Using advanced, state of the art semiconductors and
circuits, the Beckwith Electric M-0245C achieves an
overall stability and resolution unattainable with other
techniques. Modern hybrid and monolithic
semiconductors are used to gain temperature stability
without critical compensation or trimming. Unique,
patented circuitry allows precise phase measurement
over a wide range of frequency, voltage and
temperature; while operating within ±1% of the
theoretical speed limit for phase measurement.
2.0 Theory of Operation
Refer to Figure 1, Block Diagram. Each input (Motor
Bus, Line) is passed through a transformer and scaled
down from 120 V ac to 6 V ac. If variable speed motor
control is used on the motor bus, the variable speed
motor application option should be specified, which
places a dual channel low pass active filter after each
input transformer. This eliminates false zero crossing
triggering due to commutated bus voltage waveforms.
The scaled down voltages are converted into dc
voltages by the Ac to Dc Converters. These converters
are active full-wave rectifiers and filters that eliminate
the diode drop typical of conventional full-wave
rectifiers, which are highly temperature-dependent.
Full-wave rectification was chosen over half-wave
rectification because the filter response time is much
faster for a given ripple voltage. This is due to the fact
that full-wave rectification contains no fundamental
frequency components, only harmonics. The Upper
and Lower Voltage Comparitors compare the output
of the Ac to Dc Converter to a portion of a highly
stable hybrid 10 V reference. LEDs located on the
front panel indicate the condition of the Line voltage
with reference to the UPPER and LOWER VOLTAGE
LIMIT settings.
Two Zero-Crossing Detectors generate rectangular
waveforms at the zero crossing of each input. A logic
gate provides a pulse width that is proportional to the
phase difference between each input, which is then
integrated and sampled each half cycle of the highest
frequency input. This sampled voltage is an accurate
measure of the phase difference and is updated
once every 8.3 ms. The sampled voltage varies from
0 to +10 V for a phase difference change of 0 to
±180°. The sampled phase voltage is compared to
the extremely stable hybrid voltage reference. The
compared signal is an indication of the phase
difference with reference to the front panel PHASE
ANGLE LIMIT setting. Rear terminal TB1-5 allows
external monitoring of the phase difference sampled
voltage, referenced as “Phase Angle Analog Output.”
Power is provided by the Power Supply, which
supplies ±24 V dc, ±15 V dc and the precision 10 V
reference used for comparison. The supply is
designed to operate from 108 V ac to 132 V ac input
and is electrically isolated from all other inputs and
outputs. The Logic Network monitors all functions
including power supply voltages. Upon receiving a
logic “1” from the enable input and the appropriate
logic conditions from the Phase Angle, Upper Voltage,
and Lower Voltage Comparitors; the Logic Network
outputs a breaker close signal to the Breaker Close
Network. Terminals A and B are electrically shorted
by the Breaker Close Network until one of the
controlling logic conditions is false or logic “1.”
Motor Bus Undervoltage Monitor
The Motor Bus Undervoltage Detector will disable
the relay if the voltage decays below 25% during a
bus transfer sequence. This will ensure that the phase
measurement circuitry does not misoperate during a
low voltage condition.
Input Loss Protection
The M-0245C has been designed with an Input Loss
Detector circuit to minimize the possibility of the output
contacts closing due to sudden loss of the VT input
sources. The M-0245C output contact is forced to
the normally open state for any of the following
conditions:
1. Sudden drop in the line V.T. voltage
magnitude.
2. Sudden drop in the bus V.T. voltage
magnitude.
3. Bus V.T. voltage less than 0.25%.
4. Rate of change of phase, as detected by
the M-0245C circuitry, is greater than
2900°/sec. (8 Hz frequency difference).

–2–
M-0245C Instruction Book
If under warranty, units will be repaired rapidly and
returned at no cost and with return transportation paid
if the fault is found to be due to workmanship or failure
of material. If a unit is under warranty and express
shipment for return of the repaired unit is requested,
shipping charges will be billed at the current rate. If
the fault is due to abuse or misuse, or if the unit is out
of warranty, a modest charge will be made. Repair
can normally be expected to take two weeks, plus
shipping time. If faster service is required, it should
be requested at the time of return.
To help in analyzing the problem, a complete
description of the malfunction and conditions leading
to the failure should be included with the unit.
However, if you choose to repair the unit, it is
necessary to be completely familiar with the circuitry
involved, and have an adequate understanding of
field effect devices. Be sure to carefully read the
WARNING page at the beginning of this manual.
To gain access to the circuit board, remove the top
and bottom cover of the unit. Components can then
be easily tested or changed. It is suggested that first
a visual inspection be made for any component that
does not appear normal or appears to have
overheated. Analysis of the circuit will then often lead
to the cause of the failure and components that need
to be replaced.
If no obvious problems exist, it is suggested that the
TEST and CALIBRATION PROCEDURES be
followed until a portion of a circuit is detected which
does not perform as expected or until a calibration
point is found which will not meet requirements. These
procedures should lead to a determination of the
defective component.
▲CAUTION: Do not reverse polarity of the V.T.
leads to the rear terminal block if the unit is taken out
of service for maintenance.
The possibility still remains, however, that under certain
conditions (i.e., loose wires causing an intermittent
contact) the internal circuitry may not be able to
detect the loss, and the output contact could close
when the unit is initiated. Therefore, as a safeguard,
the “Close to Enable Sync Check” contact from TB1-
20 to TB1-21 should be closed only during the time
required for the transfer sequence to be completed.
3.0 Maintenance
Due to the extremely sophisticated nature of the
circuitry in the M-0245C, field repair is not
recommended. All units are fully calibrated at the
factory prior to shipment; there is no need to re-
calibrate a unit prior to initial installation. Calibration
is only required after a component is replaced.
In the event that a unit does not operate properly, it
should be established that the problem is caused by
malfunction of a Beckwith Electric unit and not caused
by an external fault or wiring error. Once this is
determined, the entire unit should be returned to
Beckwith Electric. Pack the unit carefully (in the
original carton if possible), assuring that there is
adequate packing material to protect the contents.
■ NOTE: Any equipment returned for repair must
be sent with transportation charges
prepaid. The equipment must remain the
property of the user. The warranty is void
if the value of the unit is invoiced to
Beckwith Electric at the time of return or if
the unit is returned with transportation
charges collect.

–3–
Figure 1 Block Diagram
LOWER
VOLTAGE
COMPARATOR
HIGH-SPEED
PHASE
MEASURING
NETWORK
1 V/18°
RATE OF
CHANGE OF
Ø> 2900°/sec
BUS UNDER-
VOLTAGE
DETECTOR
<25%
INPUT LOSS
DETECTOR
LOGIC
NETWORK
OPTICAL
SOLID-STATE
BREAKER
CLOSE
NETWORK
TRANSIENT
ISOLATED
POWER
SUPPLY
BREAKER
CLOSE
OUTPUT
TRANSIENT
PROTECTION
120 VAC
60 Hz
POWER
SUPPLY
MONITOR
ACTIVE
AC to DC
CONVERTER
BUFFER
AMPLIFIER
ENABLE
SYNC-CHECK
INPUT
BUS VOLTAGE
ANALOG OUTPUT
1 V/20 V ac
PHASE ANGLE
COMPARATOR PHASE OK
1 V/20 V ac
BLOCK CLOSING
STEP-DOWN
ISOLATION
TRANSFORMER
MOTOR
BUS
INPUT
TRANSIENT
PROTECTION
ACTIVE
AC to DC
CONVERTER
UPPER
VOLTAGE
COMPARATOR
MAIN
POWER
SUPPLY
NETWORK
LINE VOLTAGE
ANALOG OUTPUT
1 V/20 V ac
1 V/20 V ac INPUT LOSS
DETECTOR
LINE
INPUT TRANSIENT
PROTECTION
STEP-DOWN
ISOLATION
TRANSFORMER
VARIABLE
SPEED
MOTOR
VARIABLE
SPEED
MOTOR
PHASE ANGLE
ANALOG OUTPUT

–4–
M-0245C Instruction Book
4.0 Test Procedure
■■
■■
■NOTE: Values that change for the 50 Hz Operation
option are shown in brackets.
Refer to Figure 2, External Connections, and Figure 6,
Component Location, in conjunction with this section.
Equipment Required
1. A variable frequency source with phase
angle control capable of providing 140 V
rms with a minimum phase setting
resolution of 1°.
2. A fixed 60 [50] Hz frequency source
capable of providing 140 V rms with a
minimum phase setting resolution of 1°
rms.
3. Two (2) digital multimeters (DMMs) with
ac and dc accuracy of ±0.2% of full scale;
Hewlett-Packard model 3465A or
equivalent.
4. A dual trace oscilloscope; Tektronics, Inc.
model 465 or equivalent.
5. A digital phase angle meter with an
accuracy of ±0.5°.
6. A synchroscope, if available.
7. An incandescent bulb and dc battery
source.
■NOTE: The two ac sources above should be
phase-locked to each other.
4.1 Component Replacement
Procedure
1. The M-0245C printed circuit board has been
coated with a moisture-resistant, conformal
coating. If a component needs to be
changed, carefully scrape away the coating
surrounding the component using a small,
sharp knife; being careful not to damage
the foil on the printed circuit board.
2. Clip out the old component and discard.
▲CAUTION: Do not attempt to melt the solder and
push the new component through the hole, as the
leads are likely to catch the edge of the foil and lift it
off the board.
3. Remove the clipped wires using a solder
wick or syringe. Be sure to leave the holes
clear to facilitate insertion of the new
component.
4. When replacing integrated circuits, make
sure to insert the unit into the transipad so
that the tab fits into the slot. Once this is
done, there is only one way to insert the
combination into the printed circuit board.
5. Use a Weller Controlled Output Soldering
Station, model MTCPL, 60 W, 120 V,
50/60 Hz with a grounded tip or equivalent
equipment when soldering in new
components.
4.2 Test Procedure
Upper Voltage Limit
1. Set the UPPER VOLTAGE LIMIT control
to 125 V rms.
2. Apply the variable source at 120 V rms,
60 [50] Hz to TB1-1 and TB1-2. Note that
TB1-1 is the Hot terminal. This source will
later be referred to as the “Motor Bus
voltage input.”
3. Apply the fixed source at 120 V rms, 60
[50] Hz to TB1-3 and TB1-4, and TB1-26
and TB1-27. Note that TB1-4 and TB1-27
are the Hot terminals. This source will
later be referred to as the “Line voltage
input.”
4. The UPPER VOLTAGE LIMIT-LINE LED
should light.
5. Slowly raise the Line voltage input to
approximately 125 V rms.
6. The UPPER VOLTAGE LIMIT-LINE LED
should go out as the Line voltage passes
125 V rms.
7. Slowly reduce the Line voltage input; the
UPPER VOLTAGE LIMIT-LINE LED
should light as the voltage level drops
below 125 V rms.
8. Return the Line voltage input to 120 V
rms.
9. Repeat steps 3 through 7 with the UPPER
VOLTAGE LIMIT dial set at 115 V rms,
then at 135 V rms.
Lower Voltage Limit
1. Set the LOWER VOLTAGE LIMIT dial at
105 V rms.
2. Adjust the Line voltage input to
approximately 106 V rms.
3. Adjust the Bus voltage input to 120 V rms.

–5–
■NOTE: To prevent the voltage level detection
circuit outputs from oscillating, there is
approximately 0.5 V rms hysteresis
between when the LEDs turn on and turn
off, within a dial setting accuracy of K2%
of full scale.
4. The LOWER VOLTAGE-LINE LED should
light.
5. Slowly reduce the Line voltage; the LOWER
VOLTAGE LIMIT-LINE LED should go out
as the Line voltage input drops below 105
V rms.
6. Slowly increase the Line voltage input; the
LOWER VOLTAGE LIMIT-LINE LED
should light as the voltage level passes
105 V rms.
7. Return the Line voltage input to 120 V rms.
8. Repeat steps 3 through 6 with the LOWER
VOLTAGE LIMIT set at 95 V rms, then at
115 V rms.
Phase Angle Limit
■NOTE: The following section is written for a 60°
full scale unit. Multiply accordingly for other
scale options.
1. Adjust the Line voltage input to 120 V rms,
60 [50] Hz.
2. Adjust the Motor Bus voltage input to 120 V
rms, 60 [50] Hz.
3. The phase angle meter reading and
synchroscope should show a stable phase
angle.
4. Set the PHASE ANGLE LIMIT dial at
midscale (30°).
5. Adjust the phase angle between the Line
and Motor Bus voltage inputs to 29.5°.
■NOTE: To prevent the voltage level detection
circuit outputs from oscillating, there is
approximately 0.5 V rms hysteresis
between when the LEDs turn on and turn
off, within a dial setting accuracy of K2%
of full scale.
6. The PHASE ANGLE OK LED should light.
7. Slowly increase the phase angle between
the sources; the PHASE ANGLE OK LED
should go out as the phase angle passes
30°.
8. Slowly reduce the phase angle; the
PHASE ANGLE OK LED should come on
as the phase angle drops below 30°.
9. Repeat steps 4 through 8 with the PHASE
ANGLE LIMIT dial set at 10°and 50°.
10. Return both inputs to 120 V rms, 60
[50] Hz.
Voltage Analog Output
1. Connect the positive lead of the multimeter
to TB1-28.
2. Connect the negative (common) lead of
the multimeter to TB1-7.
3. The dc voltage reading should be
proportional to the Line voltage input ac
level, which should be 0 to 7 V dc as the
Line voltage input varies from 0 to 140 V
rms. The accuracy should be K2% of full
scale.
4. Move the DMM positive lead from TB1-28
to TB1-18. The negative lead remains on
TB1-7.
5. The dc voltage reading should be 0 to 7 V
dc as the Motor Bus voltage input varies
from 0 to 140 V rms. The accuracy should
be ±2% of full scale.
Phase Angle Analog Output
1. Connect the DMM positive lead to TB1-5.
2. Connect the DMM negative lead to TB1-7.
3. The dc voltage reading should be 0 to 10
V dc as the phase angle between the Line
input and the Motor Bus input changes
from 0°to 180°. The accuracy should be
±1% of full scale.
Voltage Status Output Contact
1. Place one ohmmeter across TB1-22 and
TB1-23.
2. Set the UPPER VOLTAGE LIMIT dial at
125 V rms.
3. Set the LOWER VOLTAGE LIMIT dial at
105 V rms.
4. Adjust the Motor Bus voltage input level to
120 V rms, 60 [50] Hz.
5. Adjust the Line voltage input level to 120 V
rms, 60 [50] Hz.
6. The VOLTAGE LIMIT LED should be lit.
7. The Voltage Status Contact from TB1-22
to TB1-23 should be closed.
8. Set the UPPER VOLTAGE LIMIT dial to
115 V rms.
9. The Voltage Status Contact from TB1-22
to TB1-23 should open when the UPPER
VOLTAGE LIMIT-LINE LED is off.

–6–
M-0245C Instruction Book
Motor Bus Voltage Analog
Output
0 Volts
Enable Sync-Check Input
28 1
AH
TB1
TB2
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
A
B
C
D
H
+
-
Motor Bus Potential Input Hot
Motor Bus Potential Input Neutral
Line Potential Input Neutral
Line Potential Input Hot
Phase Angle Analog Output
Not used
0 Volts, Common for Analog Outputs. Should be Grounded.
Not Used
Status Contact, Closed
when Voltage OK
Status Contact, Closed when
Phase Angle OK
120 V ac Power Neutral
120 V ac Power Hot
Line Voltage Analog Output
Solid-State Breaker Close Circuit Output
Not Used
Transient Suppressor Diode
Close to Enable
Sync-Check
FUNCTION
Figure 2 External Connections

–7–
10. Return the UPPER VOLTAGE LIMIT dial
to 125 V rms.
11. The UPPER VOLTAGE LIMIT-LINE LED
should be on, and the Voltage Status
Contact from TB1-22 to TB1-23 should be
closed.
12. Move the LOWER VOLTAGE LIMIT dial
past 115 V rms to approximately 118 V
rms.
13. The Voltage Status Contact from TB1-22
to TB1-23 should be open when the LOWER
VOLTAGE LIMIT-LINE LED is off.
14. Return the LOWER VOLTAGE LIMIT dial
to 105 V rms.
15. The LOWER VOLTAGE LIMIT-LINE LED
should be on, and the Voltage Status
Contact should be closed.
Phase Angle Status Output
1. Connect a 25 W incandescent bulb and a
dc battery source across Phase Angle
Status Contact TB1-24 and TB1-25 as
shown in Figure 3, Test Setup.
2. Adjust the Line voltage input to 120 V rms,
60 [50] Hz.
3. Adjust the Motor Bus voltage input to 120
V rms, 60 [50] Hz at a 20°phase angle
with respect to the Line voltage input.
4. Set the the UPPER VOLTAGE LIMIT dial
to 125 V rms.
5. Set the LOWER VOLTAGE LIMIT dial to
105 V rms.
6. Set the PHASE ANGLE LIMIT dial to 30°.
7. Slowly increase the phase angle between
the Line and Motor Bus voltage inputs.
8. The PHASE ANGLE OK LED and the
light bulb should turn off as the phase
angle passes 30°.
9. Slowly reduce the phase angle between
the sources to below 30°; the light bulb
and the LED should light as the phase
angle passes 30°.
Breaker Close Circuit
1. Connect an incandescent bulb and a dc
battery source to the Breaker Close Circuit
Output TB2-A and TB2-B as shown in
Figure 3. Note that TB2-A is the more
positive terminal.
2. Adjust the Line voltage and Motor Bus
voltage inputs to 120 V rms, 60 [50] Hz.
3. With the phase angle between the inputs
at 20°and the PHASE ANGLE LIMIT dial
set at midscale, the incandescent bulb
and all front panel LEDs should light.
4. Slowly increase the phase angle above
30°, the light bulb and the PHASE ANGLE
OK LED should turn off.
5. Return the phase angle between the
sources to 20°.
6. The incandescent bulb should be lit.
7. Remove the jumper from the Enable Sync
Check Input TB1-20 to TB1-21.
8. The output should drop out (the bulb should
turn off) when the jumper is removed and
should light when the jumper is reapplied.
Enable Response Time
1. Adjust the Line voltage input to 120 V rms,
60 [50] Hz.
2. Adjust the Motor Bus voltage input to 120
V rms at a 20°phase angle with respect to
the Line input.
3. Place the Channel 1 scope probe on
TB1-20 and the reference on TB1-21.
4. Place the Channel 2 scope probe on
TB2-A and the reference on TB2-B.
5. Set the scope trigger mode on “Normal.”
6. Set the trigger slope level on (+).
7. Set the trigger source on Channel 1.
8. Set the horizontal sweep time at 2 ms/div.
9. Test the Enable Sync Check Input
terminals TB1-20 and TB1-21 with a
jumper to ensure proper trigger of the
sweep. Adjust the stop level dial towards
the (+) direction to observe better starting
point of the sweep. Adjust the horizontal
position, if necessary.
10. After proper triggering of the signal is
observed when the unit is enabled, push
the vertical mode to Channel 2 to monitor
the signal on the Breaker Close Circuit
Output.
11. Measure the delay time between when
the Enable Sync Check Input closes and
the Breaker Close Circuit Output TB2-A
and TB2-B signal drops to minimum by
counting the divisions on the horizontal
screen.
12. The response time between when the
Enable Sync Check Input closes and the
Breaker Close Circuit Output closes should
be approximately 5 ms K2 ms.

–8–
M-0245C Instruction Book
Phase Angle OK to Output Contact Response
Time
1. Set the PHASE ANGLE LIMIT dial to 20°.
2. Apply 120 V rms, 60 [50] Hz to the Line
voltage input.
3. Apply 120 V rms, 60 [50] Hz to the Motor
Bus voltage input at a 40°phase angle
with respect to the Line voltage input.
4. Attach the Channel 1 scope probe to CR64
cathode, with reference to TB1-7.
5. Change the scope trigger to trigger on a
decrease in phase angle.
6. Channel 2 should remain attached to
TB2-A and TB2-B.
7. Jump the phase angle to 0°.
8. Measure the time delay between the
change in phase angle and the Channel 2
signal going high.
9. The time delay should be 7 ms (minimum)
to 24 ms (maximum).
10. Change the scope trigger to trigger on an
increase in phase angle.
11. Jump the phase angle from 0°to 40°.
12. Measure the time delay between the phase
angle increasing and the output contact
opening.
13. The time delay should be 7 ms (minimum)
to 24 ms (maximum).
4.3 Phase Angle Detection Circuit
Rate of Change of Phase Angle
1. Apply 120 V ac, 60 [50] Hz to the Line
voltage input.
2. Attach the scope ground to the negative
end of C78; attach the probe to the anode
of CR8.
3. Begin to slowly adjust the Motor Bus
frequency to approximately 120 V ac,
51 Hz.
4. The pulse rate should be approximately
one pulse per cycle as the Motor Bus
frequency approaches 51 [41] Hz K1 Hz.
5. Slowly increase the Motor Bus frequency.
Pulses should stop as the frequency rises
above approximately 51 [41] Hz.
4.4 Loss of Voltage Input
Detection Circuits
Line Voltage Loss
Refer to Figure 4, Line Voltage Loss, for the following
section:
1. Apply 120 V ac, 60 [50] Hz to the Bus
voltage input.
2. Apply 120 V ac, 60 [50] Hz to the Line
voltage input.
3. Place the Channel 1 probe on the anode
of CR19.
4. Place the Channel 2 probe on the end of
R136 nearest the rear terminal block.
5. Trigger the scope on Channel 1. Set the
horizontal sweep time at 5 ms/div.
6. Completely remove the Line voltage inputs.
7. As shown in Figure 4, the Channel 1 signal
should immediately go high from –15 V to
+15 V, and Channel 2 should go low after
20 ms.
Motor Bus Voltage Loss
Refer to Figure 5 for the following section.
1. Apply 120 V ac, 60 [50] Hz to the Motor
Bus voltage input.
2. Apply 120 V ac, 60 [50] Hz to the Line
voltage input.
3. Place the Channel 1 probe on Test Point
10 (TP10); attach Channel 2 probe to TP9.
4. Trigger the scope on Channel 1. Set the
horizontal sweep time at 10 ms/div.
5. Completely remove the Motor Bus voltage
input.
6. As shown in Figure 5, the Channel 1 signal
should immediately go high from –15 V to
+15 V, and Channel 2 should go high after
approximately 50 ms.
Motor Bus Undervoltage Detector <25%
1. Reapply 120 V ac, 60 [50] Hz to the Motor
Bus voltage input.
2. Remove the Channel 1 probe.
3. Slowly reduce the Motor Bus voltage.
4. The signal on Channel 2 should go high
as the voltage level drops below 25%.

–9–
M-0245
25 W
INCANDESCENT
BULB
TB2-A
TB2-B
TB2-C
TB2-D
TB1-24
TB1-25
TB1-26
+
-
DC SOURCE
CONNECTIONS FOR BREAKER
CLOSE CIRCUIT TEST
CONNECTIONS FOR PHASE ANGLE
STATUS CONTACT TEST
25 W
INCANDESCENT
BULB
+
-
DC SOURCE
Figure 3 Test Setup

–10–
M-0245C Instruction Book
+15
-15
0
CHANNEL 1
+15
-15
0
50 MS
CHANNEL 2
20 MS
-15
0
+15
+15
-15
0
CHANNEL 1 CHANNEL 2
Figure 4 Line Voltage Loss
Figure 5 Motor Bus Voltage Loss

–11–
5.0 Typical Voltages
Conditions
1. Motor Bus, Line and Power Supply are 120 V, 60 [50] Hz.
2. Measurements are made with a true rms type digital multimeter as described in the TEST PROCEDURE
section.
3. Readings are made with the negative lead of the multimeter tied to TB1-7, except where noted.
■NOTE: The “bottom”of a component refers to the end nearest the front panel of the unit; the “top”refers to the
end nearest the rear terminal block.
FONOITACOL
TNIOPTSET GNIDAER FOEPYT MROFEVAW
82-1BTcdV40.6cd
81-1BT cdV40.6 cd
75RfodnEpoTcdV99.6cd
011RfodnEmottoB caV96.31 evaWerauS
3RfodnEmottoBcaV76.31evaWerauS
1RfodnEmottoB caV00.6 evaWeniS
701RfodnEmottoBcaV30.6evaWeniS
231RfodnEmottoB cdV00.6 cd
531RfopoTcdV74.4cd
)11PT(11tnioPtseT cdV00.01 cd
)8PT(8tnioPtseTcdV88.41-cd
)6PT(6tnioPtseT cdV78.41 cd
3RVfomottoBcdV29.22-cd
1RVfopoT cdV56.02 cd
07RCfopoTcaV47.71evaWeniS
27RCfopoT cdV56.71 evaWeniS
■NOTE: The following readings are made with the negative lead of the multimeter tied to TB2-B and with the
Enable jumper removed from TB1-20 to TB1-21.
FONOITACOL
TNIOPTSET GNIDAER FOEPYT MROFEVAW
17CfodnEevitisoPcdV97.32cd
2RVfodnEpoT cdV59.31 cd
291RfodnEpoTcdV00.0cd