Durie Hill elevator equipment on display ahead of elevator centenary celebrations and inaugural Whanganui Heritage Month

The mercury arc rectifier inside the Durie Hill elevator.

An unusual piece of equipment is on public display at the Whanganui i-Site as preparations ramp up for the Durie Hill elevator centenary celebrations.

It is a mercury arc rectifier, a vacuumed glass bulb which contains liquid mercury and converts alternating (AC) current to direct current (DC). A rectifier drives the 100-year-old Durie Hill elevator, with the one on display a spare to the operating rectifier.

Whanganui District Council facilities management officer Peter Tantrum said the elevator's rectifier was normally hidden away behind closed doors but "comes alive" when the elevator is in use.

The elevator's rectifier is one of only a few in the world to be used for public transport.

The elevator was originally supplied by the same powerhouse that generated electricity for Whanganui's tramway network, with the elevator running on 500-volt direct current electricity.

"When Whanganui's tramway closed in 1950, the Hewittic 150/6 mercury rectifier was installed in the elevator tower to convert the new AC grid supply to DC electricity so the elevator could remain operational," Tantrum said.

"Also on display [at the i-Site] is a motor and gearbox similar to the one used in the Durie Hill elevator. They are smaller versions of the Durie Hill ones and were built by the same company – Smith, Major & Stevens. They were originally installed in the Sample Room building at 72 Victoria Avenue, which later became the site of Hannahs shoe factory. They were put into storage before the building was demolished in 1999."

The rectifier "comes alive" when the elevator is operating.

The Durie Hill elevator centenary community celebration event on Saturday, August 3, kicks off the inaugural Whanganui Heritage Month.

The centenary event will run from 9am to 1pm near the Durie Hill War Memorial Tower and include market stalls, food trucks, vintage games and the opportunity to see the elevator's arc rectifier in operation. There will be vintage vehicle rides to the top of the hill and elevator patrons will receive a souvenir "golden ticket".

The event will close with the Durie Hill School ball drop.

Limited edition commemorative golden tickets for the elevator will go on sale later this week at the i-SITE and elevator for the same $2 price as a regular one-way ticket.

Whanganui Regional Heritage Trustee and district councillor Helen Craig said Heritage Month recognised the importance, quality and quantity of Whanganui's built heritage.

"With over 40 events in the programme, we are thrilled with this level of support for the very first Whanganui Heritage Month," Craig said.

The mercury arc rectifier and the Smith, Major & Stevens motor and gearbox will be on display at the i-Site, 31 Taupo Quay, until the end of August.