Eltom - Motor drive with worm gear NS-EL 30

Motor drive type NS-EL is designed to work with disconnectors, load break switches, and medium voltage earthing switches in indoor conditions. The application of the drive allows for remote or local controlv of the switch installed in the cell of the switchgear. The NS-EL can easily replace the pneumatic or manual drive type NR1-01, introducing a new standard of control and safety (remote, local or manual control possibility).

simple construction with the use of
well-tested mechanisms (2000 switching cycles)
high torque for easy manoeuvring of a wide range of medium-voltage switchgear (disconnectors, load break switches, earthing switches)
operating reliability
smooth adjustment of the angle of rotation of the output shaft in the range of 220°
easy replacement of the manual drive with the NS-EL, without having to change the existing switchgear
in the case of a power failure, manual operation is possible

Motor type	with permanent magnets
Rated voltage of the motor	24 / 110 / 220 VDC
Rated power	90 - 300 W
Motor’s rated current	0,5 A
Torque on the drive’s shaft	35 - 70 Nm
Rated mechanical durability	2000 cycles
Weight	from 8 kg (depending on chosen motor)

The motor drive unit consists of:

multi-degrees cylindrical - worm gear driven by DC series motor
limit switches switching off the motor power supply when the main shaft reaches the assumed rotation angle
terminal strip for connection of power supply and control circuits
a microswitch for electrical interlock to disconnect motor power during manual operation

The housing is made of steel sheet, covered by epoxy powered paint. The lid is mounted to the drive’s panel with 2 bolts. There is the straight-though joint in the bottom, which allows to lead the conductors to the control system.

The drive mechanism includes:

the motor with permanent magnets
intersecting axis worm gear
intersecting axis rack – type gear for manual opening

The electric motor drives a shaft through a worm gear which is clamped together by means of a fork. The rotation angle of the output shaft is limited by limit switches to 220°. The angle of rotation of theoutput shaft is adjusted by means of limit switches mounted on the distribution finger plate. Byloosening the M3 screw, the angle of the output shaft can be infinitely adjusted up to 220°.

To operate the drive:

pull out the damper (placed upper or on the left side) which blocks the hole in the left side, that causes the blockade of the operating of electric motor
insert the crank in the hole (which opens when pulling out the damper)
rotate right (to close) or left (to open)
after pulling out the operating lever, it is necessary to insert the damper to unlock the motor for electrical operating

The drive is fastened to the support structure using two M10 screws. The wall on which the drive is mounted should be sufficiently rigid, ensuring a certain transfer of the electric manoeuvring torque.