On-load tap-changer for network or generator operation, electric arc furnaces, HVDC, electrolysis, inverters, phase shifters and auto transformers

Customer information


Technical Data

Max. rated through-current single-phase: 1,500 A
Max. rated through-current three-phase: 600 A
Max. rated step voltage 3,300 V
Max. rated switching capacity single-phase: 3,500 kVA
Max. rated switching capacity three-phase: 1,500 kVA
Max. voltage for operational equipment Um 72.5-300 kV
Application at neutral point (three-phase)or at any selectable winding position.
Operating positions without change-over selector 22 max.
With change-over selector: 35 max.
With multiple coarse selector: 107 max.


MR has successfully manufactured and sold VACUTAP®-brand vacuum tap changers, which offer countless advantages over oil-based technology, for many years.
This is why many clients around the world have fully switched to vacuum technology from MR.
In light of this, after nearly 50 years, we have removed the OILTAP® M on-load tap changer from our product range and will be stopping series production as of December 31, 2020.

As part of our after-sales services, we will of course continue to provide spare parts, repair services and expert technical support beyond the discontinuation date.

The mechanically compatible successor is the VACUTAP® VM, which was introduced in 2011.