Specifications
Type SSM Specication Guide
10 Low Voltage Products & Systems
1SXU132173M0201 [AC 1007.2] - 2/02 ABB Inc. • 888-385-1221 • www.abb.com/lowvoltage
(i) The incoming line section door cannot be opened if the disconnect switch is in the closed
position. The disconnect switch cannot be closed if the incoming line section door is open.
(ii) All other associated doors in sections containing medium voltage potential shall be interlocked
with the incoming line section door by either direct mechanical means or by use of Kirk-key
interlock mechanisms.
(d) A viewing window in the Main Incoming Power Compartment shall allow visual inspection of the
disconnect blade status prior to opening the door.
(e) A separate knife arm shall bond the disconnect mechanism to grouõd when fully open.
2) Power Fuses: As a NEMA class E2 controller, current limiting primary power fuses shall be provided for
each incoming phase.
(a) Fuses shall be ANSI class “R” for motor starting duty, sized according to motor locked rotor current
and coordinated with the overload relay. Fuse and overload coordination shall be designed to allow the
controller and contactor to clear low and medium level faults without blowing and without exceeding the
contactor interrupt ratings. Fuses shall be used to interrupt high level faults exceeding those ratings.
(b) Fuse holders shall include blown fuse indicators, wired to the isolation contactor circuit to disconnect
all three phases if any one of the fuses clears.
3) Isolation and Bypass Contactors: Vacuum contactors shall be provided for both In-Line Isolation and
SCR Bypass.
(a) The contactor voltage ratings shall be 7200V minimum.
(b) A sequencing feature shall control the contactors. Under normal operating conditions it will ensure that
both contactors always make and break under no-load conditions to maximize contactor life.
(c) Vacuum contactors shall be rated for maximum starting current of the unit design. The Bypass
Contactor shall be rated to be capable of emergency across-the-line start.
(d) Interrupt rating shall be in coordination with the primary fuses as per UL 347.
4) Bus Bars: Provide main horizontal phase bus bars (must specify) extending the entire length of the
starter lineup. Bus bar material shall be tin-plated or silver-plated copper. All bus ratings shall be as per UL
Standard 347.
(a) Bus bars shall be braced with non-tracking re resistant non-hygroscopic insulation supports and shall
have a minimum fault current rating of 78,000 Amps.
(b) All bus connections shall use 2 bolts minimum, with Belleville spring washers to ensure tightness.
Splice kits for each shipping split shall be included.
(c) A continuous ground bus bar with a minimum rating of 600 Amps shall extend the entire length of
the starter lineup near the bottom of each enclosure. A grounding strap shall connect each vertically
adjacent compartment and also tie the grounding arm of the disconnect switch to the main ground bus
bar.
(d) Splice kits for each shipping split shall be provided when horizontal bussing is specied.
5) Rated Short Circuit Amps: Starter and contactors shall be rated for 50kA RMS symmetrical. The
entire assembly as a NEMA Class E2 controller shall have fault withstand ratings as per UL 347 of
200MVA symmetrical at up to 2300V
350MVA symmetrical at up to 4160V
6) Overall BIL Rating: Entire starter assembly shall have a BIL (Basic Impulse Level) rating of 60kV.
7) Insulation Rating: Standard insulation design shall be for 15kV. Insulation shall be tested for dielectric
voltage withstand of 30kV for 60 seconds.