Electrical Connection; Star-Delta Start; Operation With Frequency Inverter (Fi); Operation With Soft Starter - Bitzer CM-SW-01 Information Technique

5 Electrical connection

Keep the compressor module energised when the mo-
tor is not running. This ensures an unloaded start. De-
energise the module only if a long standstill period of
the compressor or maintenance is planned.
With CS. compressors, the module switches on the oil
heater, if necessary, thus ensuring the lubricity of the
oil even after a longer standstill period.
CSW105 compressors have a connection for oil return
as an option for systems with flooded evaporator. For
the connection position, see Operating Instructions
SB-170, chapter mounting, connections and dimen-
sional drawings, position 17. The electrical integration
of this option is shown in paths 24 to 26. The switching
times of the solenoid valve must be controlled by the
superior controller and individually tested for each sys-
tem.
The economiser (ECO) is shown in path 31 in all
schematic wiring diagrams. This is an option of each
compressor. The superior controller controls switch-on
and shut-off, if necessary.
Path 52 describes the terminal box heater. It can be in-
stalled in HS. and CS. compressors as an option.

5.1 Star-delta start

The labeling of the terminals CN2:1 and CN2:2 for the
connection of the motor contactors applies for part
winding motors. Star-delta motors are connected in a
different way. Each schematic wiring diagram shows
the correct connection.

5.2 Operation with frequency inverter (FI)

The FI used must have
• either a switching output that can switch on the auxil-
iary relay K18, or a switching input for a signal from
CN2:1 that can switch the FI active via Modbus.
• a switching input for a signal from the relay output
(CN2:2) that safely shuts off the FI.
Ideally, the FI is equipped with an STO (safe torque off)
that can be switched by the relay output (CN2:2). In this
case, the main contactor and the overload protective
device can be omitted. The schematic wiring diagrams
show this version.
The FI used must be able to skip frequency ranges.
This is required for safe operation of the system. During
commissioning of the system, the whole frequency
range must be checked very carefully for abnormal vi-
brations and critical frequencies must be skipped.
ST-150-4
▶ For semi-hermetic compressors: Prepare the motor
connection for FI operation. To do so, bridge the mo-
tor terminals for direct-on-line start. Affixed to the in-
side of the terminal box cover is a sticker that de-
scribes the motor connection in detail.
▶ Operate the compressor only within the permitted
frequency ranges specified in the online document
ST-420.

5.3 Operation with soft starter

Operation with soft starter is only possible under certain
conditions after consultation with BITZER. Data upon
request.
5.4 Setting the time relay control in accordance
with the drive type.
In the standard state of delivery, the CM-SW-01 is pro-
grammed for star-delta start.
Open drive compressors are usually driven by a star-
delta motor, but other motors can be used as well. This
is why for open drive compressors equipped with a part
winding motor and in FI operation, the time relay con-
trol suitable for the drive type must be set using the
BEST SOFTWARE, see see chapter Selecting the mo-
tor start function, page 60.

5.5 Representation of components and cables

Components
• Standard scope of supply
These components are filled in grey in the schematic
diagrams, slightly darker than the optional compon-
ents.
• Optionally available components are filled in light
grey.
• Components not included in the BITZER portfolio are
filled in white.
• Compressor options that are not connected via the
module are dashed.
Motor connection in the terminal box
The terminal plates of the compressors vary depending
on the motor power. Therefore, the motor connection is
only shown schematically and surrounded by a dashed
line. There is a sticker on the inside of the terminal box
cover that describes the motor connection in detail.
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