Cemented and enamelled wiredound resistors model PMO

Professional resistors with extremely high overload characteristics, which are mechanically very robust and non-inflammable, with excellent insulation. The joints obtained with electric welding and the large size of the terminals were designed to support strong, brief overloads of short duration and are particularly suitable for use where a low resistive value and high dissipation capacity are required.
The external protection of the resistor consists of a ceramic cement lining.
The resistive element consists of a plate in Ni-Cr alloy or twisted constantan, on an extremely high quality cylindrical ceramic support.

ELECTRICAL CHARACTERISTICS

· Ohm values availablesee standard limits indicated in the table
· Standard tolerance: ± 15% for values > 1 ohm
· ± 20% for values < 1 ohm
· Temperature coefficient ≤ 100 ppm/°C
· Insulation resistance > 100 MOhm (500 Vdc)
· Max operating temperature: 400 °C

MAXIMUM LOAD LIMIT

The nominal power Pn shown in the table refers to resistors placed horizontally and free in naturally circulating air, with an environmental temperature of 25° C.
With forced ventilation the nominal power dissipation capacity of the resistor increases as a function of the air speed.


 
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