250W ÷ 500W

Industrial automation, Energy

Dynamic braking, Charge/discharge capacitors

IP55, Wire wound on mica plate coated with cement filled with quarzite sand and sealed with aluminum plug

Ohmic values out of range, Special tolerance on resistance (2%, 1%), Special cables, Different cable length

Thermal switch, Heat-sink, Fixing metal plate


The resistor is marked on the housing with indelible ink high temperature
FAIRFILD – RFK 500 150R 5% WW/YY (week / year)


Warning: Units must never be mounted with the terminals uppermost


The resistor is packed in a way to preserve incidental damages due to transport. To avoid resistor’s break we recommend to never take it from the cables and to handle with care inside the original boxes provided by the factory.


Every effort has been made to ensure that the information in this datasheet is accurate. Fairfild is not responsible for printing or clerical errors. All properties and characteristics mentioned in this datasheet are only for informational purposes. The information in this datasheet is offered solely for your consideration and should not be taken as a warranty or representation for which we assume legal responsibility. The customer bears all responsibility for use and application of Fairfild products. There is no responsibility of the manufacturer for any damage to persons and properties in case of improper use. Fairfild reserves the right to change specifications without prior notice.


This datasheet is subject to copyright. Fairfild reserves all rights of translation in any language, reprinting, re-use of illustrations.
No part of this publication may be reproduced or transmitted in any form or by any means, electronic, mechanical, photocopying, without the written permission of the copyrighted owner Fairfild, Italy. Violations may be subject to legal proceedings involving monetary damages as well as compensation for costs and legal fees under Italian copyright law and regulation within the European Union.

Ordering information

Y T : Internal thermal switch 160±5°C (rated voltage: 250 V; rated current: 2,5 A; leads single core conductor silicone rubber insulated cross section 0,25 mm2 length 300 mm).
XXX Model 250, 350, 500
RRRR Resistance value (nominal at 20°C)
RFK 500 150R 5%
RFK is the name of the product
500 is the model
150R means 150 Ω that is the nominal ohmic value at 20°C
5% is the tolerance on the ohmic value, in this case the value of the resistor is accepted when is within 142.5 Ω ÷ 157.5 Ω