Copyright March 2001 – Steve Corkill
This manual subject to copyright and not to be copied without the express permission of Corkill Systems Limited
CSLVXXX-MANUAL-2013.DOC Page 3 June 5, 2013
1. General Information
The name “Varivac” is a protected Trademark belonging to Corkill Systems Limited,
unauthorised use of this name will lead to prosecution.
Varivac is available in standard motor sizes from 4 kilowatts to 30 kilowatts, model CSLV4B
has a 4 kilowatt capacity, CSLV5B is 5.5 kilowatt, etc.
A kit is available called the tandem kit witch will convert the VARIVAC into a Tandem pump
controller, this model controls two motors simultaneously and has individual motor circuit-
breakers to protect the motors. The Varivac should be sized for the combined rating of the
motors, e.g. 1 x 11Kw + 1 x 7.5Kw motor = 18.5Kw, therefore the model Varivac to be
ordered is a model CSLV18.5B and should be ordered with a tandem kit, part number
CSLVTANDEMKIT. Note; please specify sizes or current of motors when ordering the tandem
kit to ensure it is sent with the correct size motor overloads fitted.
Please note that not all sizes are available in single phase and dual phase units and the next
size up model may need to be purchased.
Tandem pump systems have been documented to be more economic to run with two motors
running, rather than switching one of the two motors off, plus the total reserve of the
combined motors is instantly available when required.
Cabling and Motor
The Varivac must be permanently wired on a dedicated circuit with protection according to the
controller specification sheet current ratings. The Varivac needs a continuous supply to
withstand its work environment (often damp and cold) and to allow for the ramp down function
to work correctly. If remote on/off switching is required, use the “remote start” terminals on the
Varivac.
Motor cables must be EMC type, 4 core screened with a dedicated earth conductor. This is an
essential factor in lowering the SCC in the plant.
This drive is C-Tick compliant and to comply with installation procedures metal glands must
be used on both the motor and controller. Example of a metal gland shown below.
If metal glands aren’t used, bond the screen using the supplied clamp at the Varivac. “Pigtail”
earths should be avoided at all times. The EMC cable screen must be bonded to earth at both
ends. Keep the motor tails as short as possible and clear of the incoming cable to prevent an
aerial effect. Use the following minimum sizes for 3 phase units, 2.5mm for up to 7.5Kw,
4.0mm for 11Kw and 15Kw, 6.0mm for 18.5Kw and over and on single phase units, 4mm for
up to 7.5Kw, 6mm for 15Kw and 15Kw, 8.0mm for 18.5Kw and over. Do not undersize cables,
larger is better to assist removal of RFI.
The above is also critical if cow ID systems are in use or being contemplated. The screen
should be retained over the cable as close as possible to the termination point (do not strip
the screen at the base of the switchboard and then run motor tails adjacent to other wiring -
the RFI effect will be transferred into any adjacent cables).
