16
AGL_AC_ST_YRH_EN_Rev01
Cable glands have a major influence on the protection class of the terminal box. Emerson strongly
recommends using appropriate cable glands according to EN 50262 in order to reach the rated
protection class. An example of a correct electrical installation is shown in
Figure 15
below.
Figure 15: IP56 terminal box on YRH(V)* compressors
4.4 Motor winding
YRH(V)*KTE/KTG horizontal scroll compressors have a three-phase induction asynchronous motor.
All three-phase induction motors are connected in star.
4.5 Motor protection
Independently from the internal motor protection, fuses must be installed before the compressor. The
selection of fuses has to be made according to EN 60269-1 or EN 60204-1 and compressor
maximum operating current (MOC). Failing to install fuses before the compressor or selecting
inappropriate fuses may result in compressor failure.
Conventional inherent internal line break motor protection Klixon is provided with all TFD compressor
models covered in these guidelines. TX7 variable-speed models do not have an internal protector.
For these TX7 models, motor protection must be handled by setting the correct maximum current
value in the inverter.
4.6 Inverter operation
The whole range of fixed-speed horizontal scroll compressor models YRH72KTE/KTG and
YRH81KTE/KTG are limited to operation at 50 to 60 Hz.
Variable-speed models YRHV72KTE/KTG and YRH81KTE/KTG can be operated on inverter-derived
power over the range of 25 to 100 Hz.
The inverter drives used to power these compressors must comply with the provisions of
IEC 600034-17 standard. In particular, the motor input voltage must be limited to
1.35 kV/microsecond line-to-line impulse voltage. These provisions are required to avoid motor
insulation breakdown, to limit motor heating and to extend motor lifetime.
The compressor operating voltage must vary with
frequency according to the diagram shown in
. Matching voltage to frequency
according to these guidelines will prevent motor
saturation and overheating.
Figure 16: Voltage vs operating frequency for
YRHV*KTE/KTG TX7
120
150
180
210
240
270
300
330
360
390
420
20
30
40
50
60
70
80
90
100
110
V
o
lt
a
g
e
(
V
A
C
)
Frequency(Hz)
