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Fox Rotary Limit Switches

Fox Rotary Limit switches are suitable for use in safety critical applications. Available in ratios ranging from 1:3 to 1:2800 with snap action and slow action switch options, they can also be fitted with TER ‘Yankee’ encoders, either absolute or incremental, for use with PLC controls. Fox Rotary Limit switches are used in applications from wind turbines to theatrical stage equipment.


Fox is a device used to control the movement of industrial machinery when in need of measuring the movement on the basis of the rotation angle and/or of the number of shaft revolutions. Fox is made up by a gearmotor which transfers the movement to the cams and to the other movement detection devices placed inside it through a primary input reduction step (worm gear and helical toothed gear) and one or more secondary output steps (pairs of straight toothed gears).

Fox is used on wind turbines to control the position of the nacelle or the pitch angle of the blades. The motor that controls the rotation of a wind turbine on the yaw axis (or of the blade around its longitudinal axis) transfers the movement to the limit switch. A rotary encoder reads the rotation of the shaft, and its pulses are sent to a PLC which controls the position of the nacelle or of the blade. The movement of the shaft is also transferred, through a gearmotor, to a series of cam switches: the appropriate setting of the actuating point of the cams can signal up to four critical positions of the movement of the nacelle or of the blade.

Revolution ratios, ranging from 1:3 to 1:2870, result from the combination of different secondary output steps. Each cam can be set with great accuracy thanks to the cam adjusting screws. The auxiliary switches are of a positive opening type, thus suitable for safety functions.

Fox can be fitted with different combinations of actuators and motion detectors: sets of cams and microswitches (max. 5), potentiometers or encoders (max. 1), absolute encoder Yankee 1 for set of cams and microswitches (max. 1). It is possible to fit together sets of cams and microswitches, potentiometers, encoder and Yankee 1, thus creating a device featuring redundancy and diversity.
The limit switch is available with a flange for direct coupling to the motor. Different labels and colors are also available.

Fox features transmission and gear driving shafts made of stainless steel AISI 430F or AISI 303, worm gear transmission shaft rotating on ball bearings, self-lubricating techno-polymer gears and driving bushes, techno-polymer base and cover. All techno-polymers used for the enclosure are wear resistant and protect the equipment against water and dust.

Fox dimensions with and without a flange

General specifications

Conformity to Community Directives: 2006/95/CE 2006/42/CE
Conformity to Standards: EN 60204-1 EN 60204-32 EN 60947-1 EN60947-5-1 EN 60529
Regulations for the prevention of accidents BGV C 1 (only for Germany)
CAN/CSA-C22.2 No 14-10
UL 508
Storage ambient temperature: -40°C/+80°C
Operational ambient temperature: -40°C/+80°C
Protection degree: IP 66 / IP 67 / IP 69K
Insulation category: Class II
revolution ratios ≥1:16: max. 800 rev./min.
revolution ratios <1:16: max. 200 rev./min.
Cable entry: cable clamp M20, M20+M16, M20+M20
HALT test (data available on request)
Markings and homologations: CE cULus(pending) SIL 1 EAC

Specifications of the microswitches

AC 15 / 250 V / 3A max.
DC 13 / 60 V / 0.5A max.
Rated thermal current: 10A max.
Rated insulation voltage: 300 V
Connections: screw-type terminals with self-lifting pads
Certification: PRSL0110XX-PRSL0111XX: CE UL CSA

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