Circuit breaker CB2 supplies power to the control panel,
oil heater, and portions of the starter controls.
Circuit breaker CB3 supplies power to the oil pump. Both
CB2 and CB3 are wired in parallel with CB1 so that power
is supplied to them if the CB1 disconnect is open.
All starters must include a Carrier control module called
the Integrated Starter Module (ISM), excluding the
Benshaw solid-state starters. This module controls and moni-
tors all aspects of the starter. See the Controls section on
page 10 for additional ISM information. All starter replace-
ment parts are supplied by the starter manufacturer exclud-
ing the ISM (contact Carrier’s Replacement Component
Division [RCD]).
Unit-Mounted Solid-State Starter (Optional)
— The 19XR chiller may be equipped with a solid-state,
reduced-voltage starter (Fig. 5 and 6). This starter’s primary
function is to provide on-off control of the compressor mo-
tor. This type of starter reduces the peak starting torque,
reduces the motor inrush current, and decreases mechanical
shock. This capability is summed up by the phrase ‘‘softstart-
ing.’’ The solid-state starter is available as a 19XR option
(factory supplied and installed). The solid-state starters manu-
facturer name is located inside the starter access door.
A solid-state, reduced-voltage starter operates by reduc-
ing the starting voltage. The starting torque of a motor at full
voltage is typically 125% to 175% of the running torque.
When the voltage and the current are reduced at start-up, the
starting torque is reduced as well. The object is to reduce the
starting voltage to just the voltage necessary to develop the
torque required to get the motor moving. The voltage is re-
duced by silicon controlled rectifiers (SCRs). The voltage
and current are then ramped up in a desired period of time.
Once full voltage is reached, a bypass contactor is energized
to bypass the SCRs.
When voltage is supplied to the solid-state circuitry, the
heat sinks in the starter as well as the wires leading to
the motor and the motor terminal are at line voltage.
Do not touch the heat sinks, power wiring, or motor
terminals while voltage is present or serious injury will
result.
There is a display on the front of the Benshaw, Inc., solid-
state starters that is useful for troubleshooting and starter check-
out. The display indicates:
• voltage to the SCRs
• SCR control voltage
• power indication
• proper phasing for rotation
• start circuit energized
• over-temperature
• ground fault
• current unbalance
• run state
• software configuration
The starter is further explained in the Check Starter and
Troubleshooting Guide sections, pages 52 and 66.
REAR MOTOR
BEARING
ISOLATION
VALVE
SIGHT
GLASS
FILTER
ISOLATION
VALVE
FILTEREDUCTOR
OIL
PUMP
TXV BULB PRESSURE
TRANSDUCER
ISOLATION
VALVE
OIL
COOLER
OIL PUMP
MOTOR
OIL
HEATER
MOTOR
COOLING LINE
LABYRINTH
GAS LINE
FWD MOTOR
BEARING
OIL SUPPLY TO
FORWARD HIGH
SPEED BEARING
SIGHT GLASS
Fig. 4 — Lubrication System
9
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