Stearns SINPAC Switches Installation Instructions

Installation Instructions for SINPAC Switches

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UL Recognition

Most SINPAC Switches are recognized
under the component program of
Underwriters Laboratories E-71115. In
addition, all switches have an internal
surge protection which meets UL-244A
Specification and are tested to the
requirement of IEEE C62.41-1991,
Category A3.

Construction

SINPAC Switches are potted and
completely sealed making them
impervious to dust, dirt and moisture. It
can be

immersed in electric grade

oil as used in submersible pumps. The

unique speed sensing circuit provides
a universal design which allows a few
switches to work in most standard
single-phase motor applications
regardless of nature.

Operation

The Stearns SINPAC Switch samples
the voltage across the motor start
winding (terminals 1 and 4) then it is
fed into a comparator. The SINPAC
Switch interrupts the start capacitor
current (between terminals 2 and 3)
after the motor has accelerated to a
speed in which the cut out voltage
has been reached, generally 75% to
80% of synchronous motor speed. A
triac or inverse parallel SCRs provides
the function referred to as cut out.
Once the start circuit is cut out the
main winding accelerates the motor
rotor up to its running speed. When
an overload drops the motor speed
to approximately 50% of synchronous
speed the switch automatically
reconnects the motor start circuit. The
SINPAC Switch constantly monitors
the start or auxiliary winding for cut
in voltage and will reconnect the start
circuit once cut in voltage is reached.

Selection Procedure

CAUTION: SINPAC Switches are line

voltage compensated. Changes in the
line voltage within ±10% of nominal
115 or 230 Vac will not affect system
operation. Operation of the motor at
line voltages less than -10% of nominal
can result in reduced motor running
speeds and failure of the SINPAC
Switch to disconnect the start circuit.

1. Be sure switch series matches
motor type.

2. Be sure switch voltage rating
matches the motor start circuit
voltage.

3. Selection should be based on actual
measurement of start circuit current.

4. SINPAC Switch current rating must

meet or exceed the motor start

circuit current requirement. Always
select a SINPAC Switch with the
next higher current rating for:

a) High cycling applications: Stop

and start rates greater than 4
times/minute.

b) Long acceleration times: Greater

than 2 seconds.

c) High ambients: Ambients greater

than 55°C.

Note: Higher rated current switches

can be used in place of lower rated
switches within the same series.

5. The motor must generate a voltage
across the start or auxiliary winding
that is 20% greater than the SINPAC
Switch cut out/cut in voltage rating.

Capacitor Start and Capacitor
Start/Capacitor Run Motors

To determine the most appropriate
SINPAC Switch cut out voltage rating
for the particular motor application,
the voltage across the motor start or
auxiliary winding must be measured.
This may be accomplished in the
following manner:

1. Prepare the motor wiring for
connection of the SINPAC Switch
as shown in the Wiring Diagrams
for SINPAC Switches section of this
publication. Secure the motor to a
firm mounting surface.

2. Connect the lead wire that is to
be connected to SINPAC Switch
terminal #2 securely to the lead wire
that is to be connected to SINPAC
Switch terminal #3.

3. Connect an AC voltmeter across the
lead wires that are to be connected
to SINPAC Switch terminals #1 & #4.

4. Apply power to the motor. Observe
and record the voltage across the
motor start or auxiliary winding,
as indicated by the AC voltmeter,
with the motor operating near
synchronous speed.

CAUTION: Measurement of the start

or auxiliary winding voltage must be
done quickly to prevent damage to
the start capacitor, motor winding or
SINPAC Switch!

5. Multiply the measured voltage by

0.8 (80%). Select a SINPAC Switch
having a cut out voltage rating equal
to or less than this number.

Capacitor Start and Capacitor Start/
Capacitor Run Motors

Measured

Voltage

226V

200V-225V

*Consult factory

Voltage Across
SINPAC Switch

Terminals 1 & 2

115V

115V

115V<150V

230V<300V

Cut Out
Voltage

Rating

180V

165V

147V115V176-200V

130V115V150-175V

*

410V230V>492V

310V230V370-492V

260V230V300-369V

*

Caution: Application of 230 Vac to the

line input terminals (1 and 2) of a 115
Vac rated SINPAC Switch will result in
immediate switch failure. The switch
may rupture and emit smoke.

Important

Please read these instructions carefully
before installing, operating, or servicing
your SINPAC Switch. Failure to comply
with these instructions could cause
injury to personnel and/or damage
to property if the switch is installed
or operated incorrectly. For definition
of limited warranty/liability, contact
Rexnord Industries, Inc, Stearns
Division, 5150 S International Drive,
Cudahy, Wisconsin 53110,
[phone].

Initial Inspection and Handling

Upon receipt, check for package
damage. Note any signs of damage
on appropriate shipper forms. Upon
opening package, if concealed damage
is found, immediately file a claim with
carrier.

Check the label to verify that data
conforms to specifications of ordered
switch and the connection diagram
agrees with labeling.

Caution

1. Installation and servicing must
be made in compliance with
all local safety codes including
Occupational safety and Health Act
(OSHA). All wiring and electrical
connections must comply with the
National Electric Code (NEC) and
local electric codes in effect.

2. To prevent an electrical hazard,

disconnect power source before
working on the motor. If power
disconnect point is out of sight, lock

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Installation Instructions for SINPAC Switches Continued

disconnect in the off position and
tag to prevent accidental application
of power.

3. Make certain power source
conforms to the requirements
specified on the SINPAC Switch
nameplate.

4. Installation and servicing should
be performed only by qualified
personnel familiar with the
operation of the SINPAC Switch.

5. Determine what type of start switch
the motor presently has:

a) Externally mounted electronic

switch – go to Step 6.

b) Internally mounted electronic

switch – go to Step 6.

c) Externally or internally mounted

mechanical switch – it is not
necessary to remove the
existing centrifugal switch
actuating mechanism, but if
feasible, it should be removed
as it is no longer needed, and
can cause future mechanical
problems in the motor should
the mechanism fail. Follow the
manufacturers recommendation
when removing the shaft end
bearing, if necessary, to take off
the centrifugal actuator.

6. Remove the existing electronic
switch. Determine the existing
wiring diagram. Mark the existing
wires and determine which wires
can be reused for installation of
the SINPAC Switch. Select a
location in the motor conduit box or
endbell for mounting the SINPAC
Switch.

If a metal enclosure version of

SINPAC Switch is being used, the
switch with SINPAC Switch gasket
may be mounted on an external
mounting surface such as the
exterior of the conduit box. Plastic
enclosure versions of the SINPAC
Switch should be mounted
internally, within the conduit box,
or externally, under a capacitor
housing.

IMPORTANT: SINPAC Switch

in a metal enclosure must have
the metal enclosure grounded.

The temperature at the

mounting location should not
exceed 65°C (149°F).

TEFC/TENV motors require

external mounting of SINPAC
Switch.

7. Refer to motor manufacturer’s
wiring diagram to aid in identifying
terminal locations for the start
winding switch, start winding, start
and run capacitors (if needed) and
AC line.

8 Connect the SINPAC circuit per the

connection diagram (on Pages
18-19 or 20-21) using insulated
terminals. If the connections are
made incorrectly, the result will be
no starting torque and possible
damage to the circuit and/or motor.

CAUTION: Be sure that

appropriate insulation is used
between the terminals of the switch
and the body of the motor or
conduit box.

If mounted external to motor,

always use gasket supplied with
kit.

9. DO NOT USE a Variac to gradually
increase the voltage to the motor
starting circuit when SINPAC
Switch is installed.

10. Reassemble the motor with
SINPAC Switch installed, so as to
not damage lead wires.

11. If the motor fails to start or the start
winding does not cut out properly,
see

Troubleshooting Guide (Page

29).

12. Hipot test procedures:

Motors 250 Volts or Less and

1/2 Horsepower or Less

The motor, equipped with SINPAC

Switch, shall be tested for dielectric
withstand (hipot), by the application
of a 1200 volt sinusoidal potential,
in the range of 40-70 Hz, for 1
second. During the test, each
lead of the primary motor wiring,
accessible at the connection
board or conduit box, are to be
connected together and to one
terminal of the test equipment,
and the second test equipment
terminal is to be connected to the
accessible dead metal.

Motors 250 Volts or Less and

More Than 1/2 Horsepower

The motor, equipped with SINPAC

Switch, shall be tested for dielectric
withstand (hipot), by the application
of an 1800 volt sinusoidal potential,
in the range of 40-70 Hz, for 1
second. During the test, each
lead of the primary motor wiring,
accessible at the connection
board or conduit box, are to be
connected together and to one

terminal of the test equipment,
and the second test equipment
terminal is to be connected to the
accessible dead metal.

13.

CAUTION: The terminals of the

SINPAC Switch should not be used
as the junction for this field wiring.

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