• Company Name*
• Contact Name & Associated Details*
• Project Name & Reference Number*
• Application (Driven Machine)*
• Motor kW Rating*
• Rotor Volts*
• Rotor Amps*
• Number of Poles
• Drive (machine) Speed
• Number of Consecutive Starts per Hour from Cold*
• Number of Starts per Hour from Hot*
• Starting Torque Required*
• Start-up Time*
• Ambient Temperature or temperature Range*
• Type of Control (Open or Closed Loop)
• Control Supply (if other than 24 V DC)
• Availability of Cool Water Supply (for units that may require the addition of a
heat exchanges. Allows selection of most appropriate heat exchanger type ie
liquid to liquid or liquid to air)
• List of control & interface requirements.
* Denotes minimum information required for selection and budgeting purposes.
The electrolyte is prepared on site. The Liquid Resistance Starters is first filled to
maximum with potable water. A suitable container (~10 litres) is filled with water
electrolyte via the LRS drain valve and approximately 1/2 kilogram of the supplied
Sodium Carbonate is mixed into the container contents until completely dissolved.
The contents of the container are then returned to the LRS tank via the open lid,
evenly distributed with care to ensure that the carriage linear bearings are not
splashed. This process is repeated until the entire dose of Sodium Carbonate
delivered with the starter has been added. During the first few actual start cycles,
most of the dissolved oxygen will be driven out of the electrolyte. At this stage a
thin layer of oil (also supplied with the starter) is then floated on the electrolyte
surface to minimise evaporation.
For normal starting duty, the electrolyte should be completely drained, the tank
cleaned and fresh electrolyte added once every five years. As the amount of dry
electrolyte is minimal by weight of solution, it may be disposed of via an industrial
sewer subject to local authority approval. A document that outlines handling and
disposal of the Sodium Carbonate electrolyte is provided with each starter.
General maintenance primarily consists of topping up the electrolyte with potable
water, greasing the electrode guide rail bearings on moving electrode liquid
resistance starters and making sure all mechanical and electrical connections are
tight. This type of work is normally conducted annually or as needed.
Due to its large mass (700 to 8000 litres subject to tank capacity) the liquid
electrolyte acts as a storage unit for temperature. If for example the ambient
temperature varies between 10° C overnight and 40° C during the day, the
temperature of the liquid electrolyte would approximate the average daily
ambient temperature.
Heat exchangers are only needed in applications that require frequent starting,
have extended run up times or in applications where speed control may be
needed for machine set up purposes, eg. belt alignment on a conveyor system.
In such applications a joint decision is made on the most appropriate type of
heat exchanger, be it liquid to liquid or liquid to air, for the installation.
Compact dual and triple starters are available for multi-motor installations such as
those experienced on larger Conveyors, Mills and Crushers. These starters make it
possible to start multiple motors in tandem via a single tank assembly and present
several technical and commercial advantages.
Acceleration rates for each motor are very closely matched. This is made possible
by the fact that the electrolyte temperature and strength and hence the rotor
resistance, is exactly the same for each driven motor.
Yes, whilst standard tank assemblies and drive mechanisims are used in all of its
starters, approximately 75% of all Liquid Starters manufactured by NHP provide
control and interface to customer specifications.
Whilst Liquid Resistance Starters on their own do not provide a means of Slip
Energy Recovery, the NHP range of Liquid Starters can be made to interface
directly with dedicated Slip Energy Recovery systems.
