What a TNS-type unit is

A three-phase automatic voltage regulator with a servo correction mechanism, sized so that it can pass the starting current of a motor load while holding the output within the accuracy the drive or motor requires.

Where it is applied

Passenger and goods lifts

Elevator machine rooms with unstable supply

Other three-phase motor loads with a wide input voltage swing

What to confirm before ordering

The measured input voltage range at the machine room, not the nominal

The lift motor rating, starting method and starting current

The output tolerance required by the drive or motor manufacturer

Whether the unit needs a bypass for maintenance

The ambient temperature and the space available in the machine room

Commissioning

The unit is commissioned with the real load: the output is verified across the operating range of the lift, not just at no load.