MS220VA and MSR220VA
11660-0701-03-GB
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www.ziehl.de
ZIEHL PTC thermistor relays are conform to EN 60947-8 and are thus exchangeable. PTC-thermistors
according DIN 44081 and DIN 44082 shall be connected. PTC thermistors are suitable for the installation into
windings of electrical machines, bearings and transformers as well as to monitor the temperature of liquid
media, airflow and gases. With ATEX approval, explosion-protected equipment in explosive gas atmospheres
(marking G: gas) or in areas with combustible dust (marking D: dust) can be protected.
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Summary of features
•
1 thermistor
circuit for 1…6 PTC thermistors
•
Short-circuit detection within the thermistor circuit
•
Output relay with 1 change-over contact (co)
•
Operating status display with LED
A current monitors continuously the resistance of the sensors. In cold state, the resistance is <250 Ω per
sensor (sensor circuit < 1.
5 kΩ). The relay has picked up and contacts 11/14 are closed. The resistance of
the thermistor rises rapidly at detector operating temperature TNF. The relay release at a resistance of 3…4
kΩ and contacts 11/12 close. The devices also switch off in the case of detector or line short-circuit (< approx.
20Ω) or detector or line interruption. MS types switch on automatically when the temperature has decreased
approx. 5 °C. MSR types store the switch-off and must be reset (to be acknowledged) manually with the built-
in key button or an external push-button. Power-on is recognized as an automatic reset. With bridged
terminals Y1 and Y2, the function reclosing-lock is disabled. Then the device works like type MS.
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Connecting diagram
Us = supply voltage
S1 = off-switch
S2 = push-button on
S3 = remote reset only MSR type
H1 = indicator lamp fault
F1-F4 = fuses
K1 = contactor
PTC = PTC thermistor