Danfoss VLT HVAC Drive FC 102, Руководство по эксплуатации

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4 Commissioning
Refer to the chapter Commissioning in the VLT
®
Frequency
Converters Safe Torque Off Operating Instructions .
4.1 Operation and Maintenance
The safety function must be tested within regular intervals.
Test once per year, or within the maintenance cycle of the
plant. For recurring examinations of electrical systems in
hazardous areas, the inspection period must be kept within
3 years.
The safety test recognises 1 fault (1oo1 - 1 out of 1). One
fault between safety tests can cause loss of protection.
Commissioning test
Test the correct function of the MCB 112 by simulation of
the sensor resistance at terminals T1 and T2. This test must
also be done at maintenance services.
•
Short-circuit test: Resistance 20
Ω
in parallel to
sensor terminals T1, T2.
•
Line interruption test: Disconnect sensor line at
terminal T1 or T2.
•
Temperature test: Increase resistance 50–1500
Ω
to 4000
Ω
.
The tripping function is stated in the LCP and can be reset
manually when the failure is removed. Pay attention to the
ambient conditions in
chapter 7 Technical Specifications .
4.1.1 Monitoring Sensor Resistance
1) Short circuit
2) Tripping is not saved, and is not protected against 0 voltage
Illustration 4.1 Monitoring of Sensor Resistance
A current continuously monitors the resistance of the
sensors. In cold state, the resistance is <250
Ω
per sensor
(sensor circuit <1.5 k
Ω
). The output to terminal X44/12 is
high=1. The resistance of the sensor rises rapidly at
nominal response temperature TNF. At a resistance of 3–4
k
Ω
, output to terminal X44/12 changes to low=0. The
devices also switch off if the sensor or wire short-circuits
(<20
Ω
), or if the sensor or wire is interrupted. It switches
back on automatically when the temperature has
decreased by approximately 5
°
C.
Depending on the number of sensors, the following
tripping and release temperatures are achieved with
respect to TNF (nominal response temperature of the
sensors):
Trip temperature Release temperature
3 sensors in series TNF+5 K TNF-5 K
6 sensors in series TNF TNF-20 K
Table 4.1 Tripping and Release Temperatures
Commissioning
VLT
®
PTC Thermistor Card MCB 112
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