Danfoss DSH090 Application Manual page 43

Scroll compressors, DSH090 to DSH600 | Electrical connections
Figure 46: PTC Overheat
40 ms 460 ms
* approx. 1 second
While not compulsory, an additional thermal magnetic motor circuit breaker is still advisable for either alarm or
manual reset.
Then it must be set at the Max Operating Current value (MOC) :
• When the motor temperature is too high, then the internal PTC over temp. and module is activated.
• When the current is too high the thermal magnetic motor circuit breaker will trip before the module activate
therefore offering possibility of manual reset.
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.
DSH090 to DSH184
Compressor models DSH 090 to 184 incorporates an internal reverse vent valve which will react when the
compressor is run in reverse and will allow refrigerant to circulate through a by-pass from the suction to the
discharge. Although reverse rotation is not destructive for these models, it should be corrected as soon as possible.
Repeated reverse rotation over 24 hours may have negative impact on the bearings.
Reverse rotation will be obvious to the user as soon as power is turned on: the compressor will not build up
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 motor protection.
DSH240 to DSH600
Use a phase meter to establish the phase orders and connect line phases L1, L2 and L3 to terminals T1, T2 and T3,
respectively.
Compressor models DSH 240 to 600 are delivered with an electronic module which provides protection against
phase reversal and phase loss at start-up.
The phase sequencing and phase loss monitoring functions are active during a 5-sec window 1 second after
compressor start-up (power on L1-L2-L3).
Figure 48: Phase sequence module logic
Cp
St
Ph
0 1s
© Danfoss | Climate Solutions | 2022.10
40 ms 460 ms
1s*
6s
Figure 47: Delay timer active (after PTC over temp.)
80 ms
Cp Compressor
Ph Phase monitoring
St start
920 ms
1s*
AB288965961751en-001402 | 43