Electrical data, connections and wiring
CSR wiring provides additional motor torque
at start-up, by the use of a start capacitor in
combination with the run capacitor. The start
capacitor is only connected during the starting
operation, a potential relay is used to disconnect
it after the start sequence.
Some applications with high differential pressure
and start duty as "soft serve ice cream machine"
can require CSR wiring. This configuration
can also be used to reduce erratic starting
at unfavourable conditions such as very low
ambient temperature or weak voltage.
remains at high temperature and thus at high
resistance as long as power is connected to the
compressor. When the compressor is switched
off, the PTC cools down to its initial low resistance
and becomes available to support the next
compressor start.
It is important to provide sufficient time between
motor starts to allow the PTC to cool down
close to ambient temperature. Depending on
the ambient conditions and the cooling of the
PTC, this may take about 5 minutes. A restart
before the PTC is back to low resistance may be
successful or the motor may stall in a locked-rotor
state depending on the ambient and system’s
conditions. A locked-rotor state causes the
internal protector to open and would cause even
further delay until the overload is reset.
The following PTC types are recommended for
the MLZ/MLM single phase compressors:
CSR wiring
Nominal capacitor value
and relays
Model
Voltage code 1
208-230 V/1~/60 Hz
Voltage code 5
220-240 V/1~/50 Hz
MLZ/MLM015
305C12*
305C9* / 305C11*
MLZ/MLM019
305C9* / 305C11*
305C9* / 305C11*
MLZ/MLM021
305C9* / 305C11*
305C9* / 305C11*
MLZ/MLM026
305C12*
305C9* / 305C11*
MLZ/MLM030
305C9* / 305C11*
305C9* / 305C11*
MLZ/MLM038
305C9* / 305C11*
305C9* / 305C11*
MLZ/MLM042
305C9* / 305C11*
305C9* / 305C11*
Note: MLZ compressors with PTCSCR are not approved by UL. It is the customers’ responsibility to get final approval for the system
when required.
Compressor models
Default solution: PSC wiring
with run capacitor only
Additionnal components for CSR wiring
PSC wiring
CSR wiring
Run capacitor
Start capacitor
Relay
µF
µF
Reference
220-240 V /1/50 Hz
Motor voltage code 5
MLZ/MLM015
40
145-175
3ARR3*3AL*
RVA9CKL
MLZ/MLM019-021-026
70
145-175
3ARR3*3AL*
RVA9CKL
MLZ/MLM030
50
161-193
3ARR3*24AP*
RVA3EKL
MLZ/MLM038-042
55
88-108
3ARR3*25AS*
RVA4GKL
208-230 V / 1 / 60 Hz
Motor voltage code 1
not provided with the
compressor
MLZ/MLM015
45
145-175
3ARR3*3M*
RVA2ACKL
MLZ/MLM019-021
45
145-175
3ARR3*3M*
RVA2ACKL
MLZ/MLM026
60
88-108
3ARR3*3L*
RVA2ABKL
MLZ/MLM030
70
161-193
3ARR3*3L*
RVA2ABKL
MLZ/MLM038
55
88-108
3ARR3*25AS*
RVAA4IKL
MLZ/MLM042
80
189-227
3ARR3*3L*
RVA2ABKL
N
L1
Run capacitor
PTC
Thermostat
C
S
R
IOL
N
L1
Thermostat
Start capacitor
Start Relay
5
2
1
15 kΩ -1 w
C
S
R
Run capacitor
23
FRCC.PC.015.A8.02
Application Guidelines
