Skip to content

Series HTN Three-phase closed Voltage regulators current from 8A to 30A

Three-phase closed Voltage regulators

General Info
Metrel Voltage regulators are made of high quality parts and have followed advanced technological studies.
The cooling surfaces have been improved and increased, to avoid extra heating at the brush contact point with with the track, even under continuous and
heavy use.
The correct use is thus assured for longer periods and without performance losses.
The Voltage regulators conform to the standards VDE 0552 and international standards IEC 60989.

The Voltage regulators are designed to be rested horizontally on a bench.
The single-phase models come with a cable, bipolar led switch, output connection and protection fuse.
The three-phase models are available with a cable and bushing output.
Each model has a regulating knob and indication panel of the output power in percentage

Ambient Temperature
The Voltage regulators are designed to assure a correct function up to 40° C. Higher temperatures need a forced cooling system or a reduction of the
Voltage regulator’s services by 15% for every extra 10° C (ex.: a 20 A Voltage regulator must be reduced to 17 A max).


No particular maintenance is needed, when the Voltage regulator is used in normal conditions. Periodical cleaning is required by eliminating dust from the
contacts track, along with a check up of the brush, controlling that it is intact and long enough to allow a correct pressure of the spring .
In dirty and salty surroundings, it is advisable to clean the sampling track with fine sandpaper or a deoxidizer.
If the brush contact is no longer safe and must be substituted, please do the following:
– with a welder, unweld the the copper cord which gives current to the brush. Loosen the slider at the output connector and when the used brush comes off,
insert a new one and reconnect it.
– tighten and adjust the slider two to three mm. from the sampling track surface

Connections and Protections
The input power must not exceed 6% of the nominal, to avoid possible coil over heating.
The output circuit, conform to the standards VDE 0552-5.69, must be protected against voltage overloading and short circuiting with fuses and thermal
The primary circuit must be protected with a delayed fuse with correct values for each output.