Buen dia ese es un ptc,es decir un protector de la linea que protege si hay un corto o elevacion del amperaje , por lo cual debes medir el transformador a ver si se fue a tierra o se quemo, te voy a pasar un link donde esta lainformacion de los tipos de ptc y como calcularlos
http://www.amwei.com/views.asp?hw_id=44
Te colocare un extracto donde se hace el calculo
An example of PTC thermistor over-current protection devices part selection for overload protection of power transformer.
An transformer has primary voltage 220V, secondary voltage 16V, secondary current 1.5A , primary current 330mA in abnormal condition, it shall enter into protective state within 10 minutes. Operating ambient temperature: -10C--+40C , temperature may rise 15--20C in normal operating state. PTC Thermistor will be installed near transformer. Please select an appropriate PTC thermistor part for primary protection.
1) Determine maximum operating voltage
Operating voltage 220V, considering power fluctuation, maximum operating voltage should be
220V x (1+20% ) =264V
Maximum operating voltage shall be 265V.
2) Determine non-trip current
According to calculation and actual measurement, primary current is 125mA in transformer normal operation. In consideration the ambient temperature in installation position may reach to 60℃ , Non-trip current in 60℃ should be 130--140mA.
3) Determine trip current
As the ambient temperature in PTC thermistor protector installation position may reach -10 ℃ , non trip current in -10 ℃ should be 320-330mA, tripping time within 5 minutes.
4) Determine rated zero power resistance at 25 centigrade. R25
PTC thermistor is in series in the primary circuit, the voltage decreasing should be possibly small, the heating power of PTC Thermistor itself also maintain possibly small. Generally, the voltage decreasing should be less than total power voltage 1%. We can get R25 through calculation
220V X 1% ÷125mA=17.6Ω
5) Determine maximum current
Trough practical measurement, primary current can reach 500mA in transformer secondary circuit in short circuit state. If considering that larger current may pass through PTC thermistor in the state of primary coil partial short circuit. The maximum current should be more than 1A .
6) Determine reference temperature and dimension of PTC thermistor over-current protection device
Maximum ambient temperature in PTC thermistor protector installation position may reach 60 ℃ , reference temperature should be 40 ℃ higher than that, then the reference temperature can be 100 ℃ . In considering cutting down cost, also PTC thermistor is not installed in the transformer windings coil, higher surface temperature won't have unfavorable effect to transformer, therefore reference temperature can also be 120 ℃ , and then the diameter of PTC Thermistor can be smaller.
7) Determine PTC thermistor over-current protection device part number.
Based on the above technical requirement, in reference of our technical data, AMZ11-10P15RH265 shall be more appropriate.
Maximum operating voltage 265V, rated zero power resistance at 25C (R25) 15 Ω±20% , non-trip current 140mA , trip current 350 mA , maximum current 1.5A , reference temperature 120 ℃ , diameter 11mm .
NOTA: Te voy a dar un ptc que tiene una tarjeta TL32GE la cual es similar a la tuya
WMZ75S. Busca el Datasheet de este componente en el buscador google