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RFP 300 H

Cross Reference

RFP 300 H

Wire wound on mica plate or coiled as a spring filled with quarzite sand and sealed with silicone plug

The RFP is a wire resistance wound on a mica cement coated plate, immersed in quartzite sand and placed in an anodized aluminium casing. Sealing is done through dielectric cement. The cables are made of PTFE. The RFP resistance exists in the Vertical version (RFP/V) and the horizontal version (RFP/H). Only the version marked UL can be purchased. Other versions available are those with thermostat, (RFP T) those with built-in fuse (RFP F) and the version with thermostat and fuse (RFP FT).

Overview Table

Min Resistance
Max Resistance
Tolerance (%)
Rated Continuos Power (W)
Protection Degree (IP)
Not Inductive
Rated insulation voltage (V)
(Clarification on Voltage definitions.pdf)
Thermal switch

These options are available for this product:*

Thermal switch, internal fuse
*Options must be ordered separately. Contact Fairfild directly.

In what sectors is this resistance used?

The main areas of application are industrial automation, energy and railway sector.

For what types of applications is it used?

The product is used: as a dynamic braking resistor, as motor starting resistance such as charging and discharging resistance in the condensers in RC circuits.

What are the electrical specifications?

The RFP family has 8 models with power ratings from 200 W to 500 W and the ohmic value ranges between 1 Ω and 820 Ω. The maximum voltage of use is 1000 V.

What are the overload conditions?

The resistance can be overloaded with respect to its nominal power based on the working cycle (insertion and rest time). For duration pulse less than one second, the overload permissible also depends on the ohmic value. For pulses of longer duration, the internal quartzite plays a decisive role in dissipating energy. See the section on overloads in the data sheet.

What is the temperature of the resistance?

The temperature of the resistance depends on the power that it will dissipate. Numerous factors influence the dissipation capacity; please consult our technical data sheet for detailed information. The graph on page 2 of the data sheet shows the relationship between the temperature on the casing and the power applied for a heating element placed horizontally. The resistance in the vertical version (RFP/V) is able to dissipate more power than the horizontally positioned resistance.
The resistance can be installed horizontally or vertically, in this case it is necessary that the cables are facing downwards. For mounting, use the 2 slots available. The provided stripped cable is used for electrical connection. The hole for earth connection is optional. The case is provided anodized.


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