Danfoss R134a Page 23 Application Manuallines Download

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Electrical data, connections and wiring

A red/green twin LED is visible on the module.
A solid green LED denotes a fault free condition.

A blinking red LED indicates an identifiable fault
condition:

Phase sequence and reverse

rotation protection

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

direction, and the motor is wound so that if the
connections are correct, the rotation will also be
correct.

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

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.

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

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.

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).

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:

The lockout may be cancelled by resetting the
power mains (disconnect L-N) for approximately
5 sec.

Compressor

start

Phase monitoring

0 1 s 6 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

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:

Voltage unbalance

Vavg = Mean voltage of phases 1, 2, 3.

V1-2 = Voltage between phases 1 & 2.

V1-3 = Voltage between phases 1 & 3.
V2-3 = Voltage between phases 2 & 3.

2 x Vavg

% voltage

unbalance =

x 100

In case of phase reverse error:

Appro. 760 ms

Appr. 1second

In case of phase loss error: