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ST01-HU1 - Bimetallic strip with holding PTC

Bilame with holding CTP for insertion into the windings of rotating machines and transformers. Customized application in single, double, triple etc ...

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PTO-PTF bimetal probe ST01 | ST01-HU1 - Bimetallic strip with holding PTC

Product features ST01-HU1 - Bimetallic strip with holding PTC

Bimetal execution: PT0

The HU1 series bimetal is equipped with a "positive locking". A PTC probe keeps the bimetal in open position by heating the element. When the nominal switching temperature is reached, the bimetal disc snaps into its reverse position and pushes the spring disc to open the contact. The PTC resistor connected in parallel permanently keeps the bimetal above its return temperature regardless of the ambient temperature. The thermal protectors can cool down again and go to the original closed state when the external operating voltage is no longer applied and / or manually disconnected.

Insertion area: Sensor for insertion into the windings of rotating machines and transformers. 

Compact and pressure-stable: Ideal for installation in a limited space, very suitable for mounting on and on windings.

Reliability and durability: constant contact pressure over the entire temperature range; Very fast switching, therefore low arc influence on the contacts.

Sensitivity to temperature: reproducible Switching temperature induced by a non-resistive and electrically discharged mechanical bimetallic disc.

Speed: Excellent thermal coupling induced by a compact switchgear.

Flexibility: Wide assortment of wires available for connection.

Air Vacuum Test Procedure - The bimetallic strips are placed in a sealed chamber. - The chamber pressure is reduced to 30 mbar. At this pressure and at a temperature between 18 and 25 ° C the bimetallic strips are immersed in a impregnating resin. Bimetallates are placed under these conditions during dry 60. - The pressure is then normally stabilized at 1 Bar. - 120 sec. later bimetallic strips are removed from the impregnating resin. After which the bimetallic strips will remain for 2 hours in an oven at a temperature of 120 ° C in order to harden the impregnating resin.

Technical data :

Max operating voltage: 500VAC 60VDC

Normal Operating Voltage / Intensity: 250VAC 6A

Number of cycles to 250VAC / 3.0A COS FI 1.0 = 10000

Number of cycles to 250VAC / 6.0A COS FI 1.0 = 3000

Number of cycles to 250VAC / 1.0A COS FI 0.45 = 10000

Contact resistance: <50mOhm

Dielectric resistance: 2.5KV

XLPE AWG22 300V cable if T ° <150 ° C

Teflon cable FEP AWG24 600V T °> 150 ° C

Teflon cable PFA AWG22 600V on request, resistant to 250 ° C

Standard cable lengths


L1 L4 = = 520 +/- 10mm

L2 L3 = = 200 +/- 5mm

L5 L6 = = 55 +/- 5mm

Dimensions L = 15 mm D = 9,4 mm h = 4,7 mm

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