Toshiba VF010H05 - Manual (Page 12)

JKSSS+ Series - 6
JKSSS+ Series 2.3 - 4.2KV
Removable conduit entry plates are provided in the bottom of the enclosure to
facilitate drilling and punching of conduit holes without exposing the equip-
ment to contamination from metal debris.
• Enclosure Finish: The enclosure is suitable for use in noncorrosive environ-
ments. The paint is ANSI 61 gray polyurethane powder over a zinc phosphate
pretreatment with a minimum thickness of 2 mil. 11 gauge steel is used in all
enclosures. All NEMA 1 & 12 units have bottom entrance plates.
• Lifting Provisions: Eyes or angles capable of supporting the maximum
weight of each shipping split are provided on the top of the enclosure.
• Power Bus: Optional main horizontal phase bus bars can be configured to
extend the entire length of the starter lineup. Bus bar material is tin-plated or
silver-plated copper. All bus ratings are per UL Standard 347.
• Bracing: Bus bars are braced with non-tracking fire resistant non-hygroscopic
insulation supports and have a minimum fault current rating of 50,000 Amps.
• Connections: All bus connections use 2 bolts minimum, with Belleville spring
washers to ensure tightness. Splice kits for each shipping split are included,
along with specific installation instructions.
• Ground Bus: A continuous ground bus bar with a minimum rating of 400
Amps extends the entire length of the starter near the bottom of each enclo-
sure. A grounding strap connects each vertically adjacent compartment and
also ties the grounding arm of the disconnect switch to the main ground bus
bar (see section 2.11).
• Seismic Qualifications: The entire starter assembly, when properly installed,
withstands vertical and horizontal accelerations typical of seismic Zones 1
through 4 as defined in the UBC. The assembly will not overturn or show
significant lateral movement, but cannot be expected to continue operating
during, or after, a seismic event.
1.5 Theory of Operation
The power of the JKSSS+ Series is in the CPU, a microprocessor based
protection and control system for the motor and starter assembly. The CPU
uses Phase Angle Firing of the SCRs to apply a reduced voltage to the motor,
and then slowly and gently increases torque through control of the voltage and
current until the motor accelerates to full speed. This starting method lowers
the starting current of the motor, reducing electrical stresses on the power
system and motor. It also reduces peak starting torque stresses on both the
motor and load mechanical components, promoting longer service life and
less downtime.
Acceleration: The JKSSS+ Series comes standard with several methods of
accelerating the motor so that it can be programmed to match almost any
industrial AC motor application.
The factory default setting applies a Voltage Ramp with Current Limit as this
has been proven the most reliable starting method for the vast majority of
applications. Using this starting method, the Initial Torque setting applies just
enough voltage to the motor to cause the motor shaft to begin to turn. This
voltage is then gradually increased over time (as per the Ramp Time setting)