Voltage Unbalance - Danfoss R134a Application Manuallines

Application Guidelines
Phase sequence and reverse
rotation protection

Voltage unbalance

Electrical data, connections and wiring
A red/green twin LED is visible on the module.
A solid green LED denotes a fault free condition.
PTC overheat
40ms 460ms 40ms 460ms
Appr. 1 second
Use a phase meter to establish the phase
orders and connect line phases L1, L2 and L3
to terminals T1, T2 and T3, respectively. The
compressor will only operate properly in a single
Compressor model SM112-124-147 have no
internal reverse rotation protection. If reverse
rotation occurs it will be obvious as soon as
power is turned on. The compressor will not
build-up any pressure, the sound level will be
abnormally high and power consumption will be
Compressor models SM/SZ084 to 185 (except
SM112-124 & 147) incorporate an internal reverse
vent valve which will react in the presence of
reverse rotation and will allow refrigerant to
circulate through a by-pass from the suction to
the discharge. Although reverse rotation is not
destructive, even over long periods of time up
to several days it should be corrected as soon
as possible. Reverse rotation will be obvious
Compressor models SY240 to SY380 are delivered
with an electronic module which provides
protection against phase reversal and loss
at start-up. Apply the recommended wiring
diagrams. The circuit should be thoroughly
checked in order to determine the cause of the
phase problem before re-energizing the control
circuit.
The phase sequencing and phase loss monitoring
functions are active during a 5 sec. window 1 sec.
after compressor start-up (power on L1-L2-L3).
Compressor
start
Phase monitoring
0 1 s
Phase sequence module logic
The operating voltage limits are shown in the
table section "Motor voltage". The voltage applied
to the motor terminals must lie within these
table limits during both start-up and normal
operations. The maximum allowable voltage
% voltage
unbalance
Vavg = Mean voltage of phases 1, 2, 3.
V1-2 = Voltage between phases 1 & 2.
A blinking red LED indicates an identifiable fault
condition:
Delay timer active (after PTC overheat)
80ms
Appr. 1 second
direction, and the motor is wound so that if the
connections are correct, the rotation will also be
correct.
minimal. In such case, shut down the compressor
immediately and connect the phases to their
proper terminals. Prolonged reverse rotation will
damage the compressor.
A phase sequence detector is strongly
recommended.
to the user as soon as power is turned on; the
compressor will not build up any pressure, the
sound level will be abnormally high and power
consumption will be minimal. If reverse rotation
symptoms occur, shut the compressor down and
connect the phases to their proper terminals. If
reverse rotation is not halted, the compressor will
cycle off on the internal motor protection.
Should one of these parameters be incorrect, the
relay would lock out (contact M1-M2 open). The
red led on the module will show the following
blink code:
In case of phase reverse error:
120 ms120 ms120 ms
In case of phase loss error:
500ms
Appr. 1second
The lockout may be cancelled by resetting the
6 s
power mains (disconnect L-N) for approximately
5 sec.
unbalance is 2%. Voltage unbalance causes high
amperage over one or several phases, which in
turn leads to overheating and possible motor
damage. Voltage unbalance is given by the
formula:
| Vavg - V1-2 | + | Vavg - V1-3 | + | Vavg - V2-3 |
=
920ms
400ms
Appro. 760 ms
500ms
2 x Vavg
V1-3 = Voltage between phases 1 & 3.
V2-3 = Voltage between phases 2 & 3.
AB237986441643en-010801
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