Wilo Rexa CUT GE, Installation And Operating Instructions Manual

Page: 165 / 1148

Appendix en
Installation and operating instructions Wilo-Rexa CUT GE 165
13.3.4.2 Monitoring of motor winding
DANGER
Risk of explosion due to overheating of the motor!
If the temperature limiter is connected incorrectly, there is a risk of explosion due to
overheating of the motor! Always connect the temperature limiter to a manual re-
activation lock. This means that a “release button” must be manually activated!
The motor is equipped with a temperature limit (1-circuit temperature monitoring). As
an option, the motor can be fitted with a temperature control and limit function (2-cir-
cuit temperature monitoring).
Depending on the version of the thermal motor monitoring, the following triggering
status must occur when the threshold value is reached:
▪ Temperature limiter (1 temperature circuit):
When the threshold is reached, deactivation with reactivation lock must take place!
▪ Temperature controller and limiter (2 temperature circuits):
When the threshold for the low temperature is reached, the motor can deactivate with
automatic reactivation. When the threshold for the high temperature is reached, the
motor must deactivate
with reactivation lock !
CAUTION! Motor damage due to overheating! In the event of automatic reactiva-
tion, comply with the specifications for the maximum switching frequency and
switching break!
Connection of the thermal motor monitoring
▪ Connect the bimetallic strip via an evaluation relay. Relay “CM-MSS” is recommended
for this. The threshold is preset.
Connection values: max. 250 V(AC), 2.5 A, cos φ = 1
▪ Connect the PTC sensor via an evaluation relay. Relay “CM-MSS” is recommended for
this. The threshold is preset.
13.3.4.3 Sealing chamber monitoring (ex-
ternal electrode)
▪ Connect the external pencil electrode via an Ex-rated evaluation relay! Relay “XR-4…” is
recommended for this.
The threshold is 30 kOhm.
▪ The connection must be made using an intrinsically safe circuit!
13.3.4.4 Frequency converter operation ▪ Type of converter: Pulse-width modulation
▪ Continuous duty: 30 Hz up to rated frequency (50 Hz or 60 Hz). Comply with the min-
imum flow velocity!
▪ Min. switching frequency: 4 kHz
▪ Max. overvoltages on the terminal board: 1350 V
▪ Output current on the frequency converter: max. 1.5 times rated current
▪ Max. overload time: 60 s
▪ Torque applications: quadratic pump curve
Speed/torque curves required are available on request!
▪ Observe additional measures with regard to EMC regulations (choice of frequency con-
verter, filters, etc.).
▪ Never exceed the rated current or rated speed of the motor.
▪ It must be possible to connect the motor’s own temperature monitoring (bimetallic
strip or PTC sensor).
▪ If the temperature class is marked as T4/T3, temperature class T3 applies.
13.3.5 Commissioning
DANGER
Risk of explosion when using non Ex-rated pumps!
Pumps without Ex rating may not be used in potentially explosive areas! There is a
risk of fatal injury due to explosion! Only use pumps which have the appropriate Ex
labelling on the rating plate within potentially explosive areas.