Specifications RC OFEL
RC linear cursor rheostats consist of one or more cylindrical porcelain tubes with an alloy wire resistive winding and by one or more sliding contacts on the winding along the lines of the cylinder, moved by a knob or with an endless screw.
These rheostats are simple, sturdy and easy to use and install.
They can be used for an infinite number of applications, especially in laboratories, whenever there is a need for adjustment of tension or current.
The company's long experience has enabled them to make the most opportune choices in terms of the materials used. The cylindrical tube in special porcelain has high mechanical resistance and resistance to thermal shock; the resistive allow used is generally constantan, which has a negligible temperature coefficient; the support plate and bored protective foils are fired after enamelling in a high temperature kiln and thus ensure that the colour is lasting and remains unaltered.
RC2 and RC3 can be supplied respectively with six or nine output terminals.
Features RC OFEL
Rheostats with graduated windings:
When the "adjustment ratio" namely the ratio between the maximum and minimum current with the rheostat closed and with the rheostat completely inserted, is high, or the law of variation of the resistance must have a particular trend, the winding is divided into several sections, realised with wires of various diameters. When ordering, it is sufficient to indicate, in addition to the overall resistance, the initial and final current, or transmit a graph showing the resistance values in several points of the rheostat.
Screw Adjustment:
If required, instead of direct hand control, the brushes can be controlled by a close-thread screw (10 mm)
This method is necessary in the event the rheostat is mounted in a position behind the control panel, or the motorised control.
Rheostat with zero excluded:
If it is necessary for the user circuit to be open in the starting position of the run of the contact, it is possible to install two collar terminals, one of which is connected to the winding, to realise the condition of "zero interrupted" or "excluded".
Use with ventilation:
RC cursor rheostats are most frequently used with inert load to test generating machines or instruments of measurement. They are installed to make ventilation possible. Since the ventilation reaches 2.5 m/sec, the rheostats can be overloaded even by 100% and even more for brief periods.
Adjustable passive loads:
A load of 2 KW, 220 V, adjustable from 2 to 0,2 KW must be realised, for example: namely from 100% to 10%, with continuity. Two RFC cemented wire resistances will be used of 48.3 (or slightly less), between them and in parallel, capable of dissipating the 2 KW foreseen with a modest amount of ventilation.
In series, an RC2 will be installed, namely an RC with two parallel resistances with an ohm value 9 times greater than the RFC, namely, about 435, realised in 6 sectors wound with diminishing diameter wires, in harmony with the diminishing of the current as a consequence of the increase of resistance inserted.
The choice of resistance values included between the minimums and maximums in the table refer to the normalised table E12.
Precision ± 10%.
Particular values available on request.
