Wiring Diagram Without Pump-Down Cycle; Ip Rating; Motor Protection; Voltage Unbalance - Danfoss Maneurop NTZ Series Application Manuallines

Application guidelines
Wiring diagram without
pump-down cycle
Control device TH
Optional short cycle timer (3 min) 180 s
Control relay KA
Compressor contactor KM
Safety lock out relay KS
H.P. switch HP
Fused disconnect Q1
Fuses F1
Compressor motor M
Discharge gas thermostat DGT

IP rating

Motor protection

Internal motor protection

Voltage unbalance

Electrical connections and wiring
CONTROL CIRCUIT
F1
The compressor terminal boxes IP rating accord-
ing to CEI 529 are:
IP55 for NTZ048 - 136
IP54 for NTZ215 - 271.
The IP ratings are only valid when correctly sized
cable glands of the same IP rating are applied.
Three phase compressors are internally protected
by a temperature / current-sensing bimetallic
protector, connected to the neutral point of the
star-connected stator windings. This internal
overload line break protects the motor against
Operating voltage limits are shown in section
"Voltage application range". The voltage applied
to motor terminals must lie within these limits
during both start-up and normal operation. The
maximum allowable voltage unbalance is 2%.
Voltage unbalance causes high amperage on one
% voltage unbalance:
Vavg = Mean voltage of phases 1, 2 and 3
V1-2 = Voltage between phases 1 and 2
F1
KA KS
KA KA
A1
T1
A3
HP
180 s
A2
LP
KS
TH
DGT
KM KA KS
overheating, current overload and locked rotor
conditions. If the motor were to be overloaded
and the protector trips, all 3-phases are cut out.
It might take up to several hours to reset and
restart the compressor.
or more phases, which in turn leads to overheat-
ing and possible motor damage.
The voltage unbalance is given by the following
formula:
|V - V |+|V - V
avg 1-2 avg 1-3
2 xV
avg
V1-3 = Voltage between phases 1 and 3
V2-3 = Voltage between phases 2 and 3.
L1 L3 L2
Q1
KM
T2
T3
M
85 52 019 - A
|+|V - V |
avg 2-3
x 100
FRCC.PC.002.A4.22
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