E21.REV

GENERATOR SYNCHRONIZING SWITCHBOARD

NOTE: MASTER COPY DATE: OCT. 30, 1984

Part 1 -	GENERAL

1)	DESCRIPTION

A.	Complete freestanding assembly containing power circuit breakers and control devices for operation, control, and synchronization of the engine generator sets.

B.	Switchboard construction to be as specified under low voltage distribution equipment.

C.	Fully automatic generator synchronizing switchboard arranged to control the operation of ----- ( ) (--- initial --- future) ----- kw, ---/--- volts, 0.8 power factor, ----- phase, ----- wire, 60 hertz in conjunction with an automatic transfer switching system.

D.	----- (space only for future generating units) engine generator control cubicles and one master control cubicle.

E.	Generator circuit breaker load terminals connected to a horizontal bus structure with full neutral and the output of the generating system connected to the essential system connected to the essential systems switchboard for distribution.

F.	Provide all interconnecting wiring for complete operation.

2)	QUALITY ASSURANCE

A.	Manufacturer shall:

1.	Have a minimum of 5 years experience in building automatic synchronized switchboard.

2.	Have a minimum of 5 successful working installations of the type of equipment specified.

3.	Maintain a competent service organization available 24 hours each day within 300 miles of project site.

4.	Manufacturer automatic transfer switches that are specified. For closer coordination, more unified responsibility, and compatibility the manufacturer of the equipment specified in this section will also be the manufacturer of the transfer switches specified for this project.

5.	Provide the coordinating wiring diagrams showing the electrical connections between the synchronization switchgear and the engine generators to permit contractor and engine generator service personnel installation and checkout of the equipment.

6.	Perform a complete operational test on his entire system and submit certified test results after architect's review of shop drawings but before shipment.

3)	SUBMITTALS

A.	Submit shop drawings showing:

1.	Dimensional space layout.

2.	Equipment drawings.

3.	Catalog cuts.

4.	Test results.

5.	Schematic wiring diagram.

6.	Block diagram.

7.	Technical data sheets.

8.	Front and section views.

9.	Weights.

10.	Provisions and locations for connection of external circuits.

11.	Circuit breaker with accessories.

12.	Current transformers.

13.	Potential transformers.

14.	Meters.

15.	Meter selection and control switches.

16.	Protection programmer.

17.	Time current curves and settings.

B.	Certificates and manuals.

1.	Certification by the Contractor that the assemblies have been properly installed, adjusted and tested.

2.	Certified copies of all of the factory and construction site test data sheets and reports for the assemblies.

3.	Complete operating and maintenance manuals including wiring diagrams, technical data sheets and information for ordering replaceable parts.

a.	Wiring diagrams with terminals identified to facilitate installation, operation and maintenance.

b.	Wiring diagrams showing the internal wiring for each item of equipment and the interconnections between the items.

4)	DESCRIPTION OF OPERATION

A.	On a loss of normal source voltage at any automatic transfer switch, a signal shall be generated to initiate an automatic sequence.

B.	On initiation of the automatic sequence, all engines shall be started. The first engine generator set to achieve 90 percent of nominal voltage and frequency shall be connected to the bus through the multiple circuit interlock discriminator. The highest priority load requiring emergency power shall then be connected. As the remaining engine generator sets start, their respective synchronizers initiate control of voltage and frequency of the oncoming set to cause synchronism with the bus. On achieving synchronism with the bus each generator breaker shall be closed and each remaining load block shall be transferred in priority sequence, until all the loads are connected to the bus Circuitry shall prevent the automatic transfer of emergency loads to the bus until there is sufficient capacity to carry the loads. Means shall be included to manually override the load addition circuits for unsupervised operation. Provide a programmable device with visual indication to permit convenient assignment and reassignment of load priority control without wiring changes.

C.	The system shall designed so that the load is reduced automatically on the failure of any plant. This mode overrides any previous manual controls to prevent overloading the emergency bus. On sensing a failure mode on a prime mover, the controls shall automatically initiate disconnect, shutdown and lockout the failed source, and reduce the connected load to within the capacity of the remaining plant(s). Controls require manual reset.

D.	After a predetermined time delay, 0-30 minutes, a solid state kilowatt sensing system shall be placed into operation to control the addition or subtracting of engines as required.

E.	On restoration of the normal source of supply at all automatic transfer switches the loads shall be retransferred to the normal source. On retransfer, the engine generator sets shall be disconnected from the main generator bus, run for an adjustable period of up to 15 minutes maximum (factory set at 15 minutes) for cooldown and then shutdown. All controls shall automatically reset for the next operation.

F.	On initiation of an automatic sequence for utility peak demand reduction operation, all engines shall be started. The first engine generator set to achieve 90 percent of nominal voltage and frequency shall be connected to the emergency bus. The first peak reduction load transfer switch shall then be signalled to transfer its load to the emergency bus. As the remaining engine generator sets start and achieve 90 percent of nominal voltage and frequency, their individual automatic synchronizers shall initiate control of voltage and frequency to bring the oncoming sets into synchronism with the bus. On achieving synchronism, the oncoming set shall be paralleled. As these oncoming sets are paralleled, the system signals additional peak load shedding transfer switches to connect their loads to the emergency bus.

.

G.	The system shall prevent transfer of load to the emergency bus until there is sufficient capacity to carry the additional loads. Means shall be included to manually override the load addition circuits for supervised operation.

H.	On termination of utility peak demand reduction operation, the loads are retransferred to the normal power source, the engine generator sets are disconnected from the bus, and run for a cool down period as previously described.

I.	If while operating in the utility peak demand reduction mode a normal source failure occurs at any essential load automatic transfer switch, peak reduction operation is automatically terminated. On receipt of signal that the normal source has failed, all peaking loads shall be automatically disconnected from the emergency bus by retransfer to normal, and all affected essential loads are transferred to the emergency bus. The system shall permit reconnection of the peak reduction loads to the emergency bus power distribution failures and when there is sufficient capacity to carry peak reduction loads.

Part 2 -	PRODUCTS

1)	MATERIALS

A.	Switchboard.

1.	Comply with the requirements of Low Voltage Distribution Equipment. Note the following additional requirements.

a.	Internal wiring: U.L. listed conductors style 1015 rated and 600 volts. Label and list all conductors and connection points.

2.	Circuit breakers:

a.	Draw-out power air type with electrical operation for opening and closing on receipt of signal.

b.	Delete the integral ground fault function (unless automatic trip can be defeated) and replace with separate ground fault units with adjustable pickup and delay and a monitor panel for visual and audible indication of ground faults.

3.	Bus bars:

a.	Bracing: a rms symmetrical amperes at AC is adequate.

4.	Specific meters:

a.	As listed in various paragraphs of this section.

B.	Solid state circuitry and electromechanical control relays and devices.

1.	Solid state circuitry.

a.	Circuit boards: Coated for protection against physical contact and corrosive atmospheres. Rigidly held in place and covered.

b.	Test points and adjustments: readily accessible.

c.	Control relays: positive binary action on or off void of creep and contact chatter.

2.	Electromechanical control relays.

a.	Rating: suitable for intended service.

b.	Contacts: gold flashed for relays in low-voltage, low-current DC control circuits. For relays in other than logic and dry contact switching, contact ratings to be suitable to make and carry duty at operating voltage.

c.	Types: plug-in with retaining clips and transparent cover.

d.	Identification: clearly marked and color coded for control voltage.

3.	Repetitive accuracies.

a.	For solid state controls, monitors, protective relays, programmers, and devices to be not less than stated values for AC powered devices in voltage range of 70-110 percent of nominal, and for DC powered devices in voltage range of 20-40 volt DC.

(1)	Voltage: Plus or minus of set point over a frequency range of 40-70 Hz.

(2)	Current: plus or minus 3 percent of set point over a frequency range of 40-70 Hz.

(3)	Frequency: plus or minus 0.2 Hz.

(4)	Power: Plus or minus of set point over a frequency range of 40-70 Hz.

(5)	Voltage difference: 1.0 v over a frequency range of 40-70 Hz.

(6)	Frequency difference: plus or minus 0.05 Hz.

(7)	Relative phase angle: plus or minus 1.0 deg at 50 or 60 Hz.

b.	Operating temperature, humidity and altitude: accuracies to be maintained for minus 20 to 65 deg C, 100 percent, 2000 meters, respectively.

4.	Transient withstand test - solid state.

a.	Circuitry to meet or exceed the transient overvoltage withstand test per NEMA ICS1-109 and the surge Withstand Capability Tests (SWC) per IEEE standard 472-1974 (ANSI C37.90A-1974).

b.	<U.L.: Meet or exceed applicable standards for components, devices and/or assemblies.

C.	Engine generator control sections.

1.	Generator control panel.

a.	Quantity: one for each engine generator set.

b.	Purpose: protect, monitor and control operation of each generator set.

c.	Type: solid state, printed circuit.

d.	Relays and circuit boards.

e.	Reverse power protective relay. (device 32).

(1)	Quantity: one for each engine generator set.

(2)	Purpose: detect generator motorizing condition.

(3)	Type: solid state.

(4)	Trip setting: adjustable from zero to 15 percent of the generator power rating.

(5)	Response: independent of frequency from 40 to 70 Hz.

(6)	Time delay: Linear for compatibility with generator characteristics. Adjustability and setting: 0.1 to 6.0 second and factory set at 2.0 seconds.

(7)	Response: To power, the inphase component of current for power factor from 0.2 to unity, leading or lagging with a repeatability within plus or minus 3.0 percent.

f.	Generator voltage protective relay (device 27) (three per cubicle).

(1)	Purpose: respond to true r.m.s. value of generated voltage.

(2)	Type: solid state.

(3)	Pick up: adjustable from 75 to 100 percent of minimal.

(4)	Drop out: adjustable from 80 to 95 percent of pick up. Zero differential for time delay reset about drop out setting.

g.	Generator frequency protective relay (device 81).

(1)	Purpose: full cycle sensing to respond to fundamental of system ignoring wave shape distortion.

(2)	Type: solid state, underfrequency.

(3)	Pick up: adjustable from 45 to 60 Hz.

(4)	Differential: adjustable from 0.1 to 10 Hz.

(5)	Underfrequency trip: zero differential for time delay reset about trim setting.

h.	Frequency/voltage time delay (device 81T and 27T).

(1)	Purpose: adjustable on drop out of both device 27 and 81 to override loading transients.

(2)	Type: solid state.

(3)	Adjustability and setting: 0.1 to 6.0 seconds and factory set at 2.0 seconds.

(4)	Repetitive accuracy: Within plus or minus 10 percent.

i.	Automatic synchronizer (device 25A).

(1)	Purpose: Synchronize generator sets with a paralleling bus.

(2)	Type: Purpose: Synchronize generator sets with a paralleling bus.

(3)	Type: Automatic, solid state.

(4)	Include:

(a)	Differential voltage, differential frequency, and differential phase detectors.

(b)	Raise/lower voltage output relays for generator voltage control.

(c)	Raise/lower frequency and phase angle control through a proportional DC output voltage.

(d)	Circuit breaker closing relay.

(5)	Differential voltage detector.

(a)	Purpose: compare voltage of oncoming generator to paralleling bus.

(b)	Adjustability and setting: 0 to plus or minus 10 percent and factory set at plus or minus 5 percent.

(c)	Repetitive accuracy: plus or minus 1.OV over specified temperature range.

(d)	Operating criteria: If voltage is not within factory set difference of plus or minus 5 percent, the circuit breaker closing relay is locked out. Simultaneously voltage adjustment is initiated through the raise/lower voltage output relay. When the oncoming generator voltage is within the preset acceptable limits, the lockout is removed.

(6)	Differential frequency detector.

(a)	Purpose: compare frequency of oncoming generator to paralleling bus.

(b)	Adjustability and setting: 0 to plus or minus 0.5 Hz and factory set at plus or minus Hz.

(c)	Operating criteria: If frequency is not within factory set difference of plus or minus 0.2 Hz, the circuit breaker closing relay is locked out. Simultaneously a DC VOLTAGE PROPORTIONAL TO THE FREQUENCY DIFFERENCE IS GENERATED CAUSING THE ENGINE GOVERNOR TO BRING THE FREQUENCY WITHIN PRESET ACCEPTABLE LIMITS. [THE LOCKOUT IS THEN REMOVED].

j.	PHASE BALANCE CURRENT RELAY (DEVICE 46).

(1)	PURPOSE: PROJECTS AGAINST GENERATOR ROTOR OVERHEATING DUE TO UNBALANCED PHASE CURRENTS.

(2)	TYPE: SOLID STATE.

(3)	PICKUP: DEFINITE TIME, CONTINUOUSLY ADJUSTABLE 0.5 TO 4 SECONDS.

k.	LOCKOUT RELAY (DEVICE 86).

(1)	PURPOSE: LOCKOUT CIRCUIT BREAKER.

(2)	TYPE: ELECTROMECHANICAL.

(3)	-----: SIMILAR TO GE Type HEA.

l.	Loss of field relay (device 40).

(1)	Purpose: protects against loss of field.

(2)	Type: electromechanical.

(3)	Manufacturer: similar to G.E. type CEH.

m.	Multiple generator interlock or dead bus relay.

(1)	Purpose: prevent multiple generator connection to dead bus.

(2)	Type: solid state discriminator.

(3)	Operating criteria: initiation of connection of first generator to bus will shift control of the remaining generators to automatic or manual synchronizing at operator's discretion.

n.	Control circuit status indicator.

(1)	Color coded, light emitting diodes on the generator control panel to indicate the following:

condition	color	---------	-----

control power fuse blown	red

generator voltage and frequency acceptable green

voltage adjust activated	red	breaker closing initiated	amber	reverse power trip setting exceeded	amber	engine start signal received	green	engine start signal fuse blown	red

o.	Engine cooldown and failure to synchronize time delay relays.

(1)	Type: solid state.

(2)	Adjustability and setting engine cooldown: 0 to 15 minutes and factory set at 15 minutes. Failure to sync: 0 to 120 seconds and factory se at 30 seconds.

(3)	Operating criteria.

(a)	Engine cooldown: Automatically bypassed on malfunction and manual shutdown of engine generator. Failure to sync: Audible and visual indication. Synchronization attempts and engine running to be unaffected.

2.	Engine control panel.

a.	Purpose: automatically start, protect and monitor engine generator.

b.	Quantity: one for each engine generator.

c.	Type: solid state.

d.	Electrically isolated contacts for:

(1)	Electronic governor control.

(2)	Electric fuel control.

(3)	Battery charger disconnect during cranking.

(4)	Common shutdown alarm annunciation.

(5)	Fan and damper control.

(6)	Generator room light switch bypass.

e.	Relays: same as and interchangeable with relays specified in Engine Generator Control section.

f.	Engine start/stop operation.

(1)	Automatic engine control: Initiate operation of engine on receipt of signal form a contact which closes for engine run and opens for engine stop.

(2)	On engine start the starting motor shall be automatically disconnected until engine comes to a complete rest.

(3)	Cranking timing device.

(a)	At least a adjustable cranking attempts, 5 to 30 seconds and factory set at 10 seconds cranking duration with 10 second rest period. (adjustable) overcurrent lockout shall occur after four unsuccessful cranking attempts. Provide means to allow for a continuous cranking cycle if required.

(b)	Provision for single cycle cranking adjustable form 35 to 210 seconds.

(c)	If any protective device operates while engine is running, engine is disconnected and stopped.

(d)	Lock out failed set requiring manual reset.

(4)	Four position engine control switch.

(a)	Off/reset: red flashing light and engraved red lettered nameplate: warning; return to automatic position for generator to function.

(b)	Automatic.

(c)	Test: engine starts and runs but is not connected to bus unless a start signal is received. When returned to auto mode, the engine shuts down.

(d)	Test on-line: engine starts and runs and is connected to bus as if a start signal is received. When returned to auto mode, the circuit breaker opens and the engine will run for its cooldown period and shut down.

3.	Alarm and status indication.

a.	Visual: alarm resettable only after fault condition is corrected.

b.	Audible: alarm which after silenced provides audible annunciation of subsequent failures.

c.	Lamp test for all visual indicators.

d.	Location: each generator control section to include readout and annunciation for

condition mode color

--------- ----	low water temperature alarm amber	low oil pressure prealarm amber	low oil pressure shutdown red	high water temperature prealarm amber

high water temperature shutdown red	overcrank shutdown red	overspeed shutdown red	circuit breaker trip shutdown red	reverse power shutdown red	failure to synchronize prealarm red	controls not in

automatic (*) flashing red	circuit breaker open status white	circuit breaker closed status green	engine running status white	battery charger failure alarm amber	control voltage failure alarm amber	generator locked out alarm flashing

amber

(*) red lettered nameplate: warning:

return to automatic position for generator to	function

4.	Synchronizing mode selector switch.

a.	Automatic position: Automatic synchronization as described in Automatic Synchronizer section.

b.	Manual position:

(1)	Automatic synchronizer disconnected.

(2)	Paralleling is manual through controls specified in Master Control Section.

(3)	Does not inhibit generator connection to dead bus through the multiple circuit interlock described earlier.

5.	Failure synchronize reset switch.

a.	Mounting pushbutton to reset "Fail to Synchronize" alarm.

6.	Metering.

a.	For each engine generator control section.

(1)	Ammeter: ampere scale.

(2)	Voltmeter: volt scale.

(3)	Kilowatt meter: kilowatt scale.

(4)	Frequency meter: 55-65 hertz scale.

(5)	Running time hour meter: 5 digit non-reset.

(6)	Ammeter voltmeter phase selector switches.

(7)	Current and fused potential transformers as required.

7.	Circuit breaker control switch with red and green position lights.

8.	Engine governor, generator voltage regulator and miscellaneous engine generator set controls.

a.	Switchboard manufacturer to mount and wire all electronic and electric controls associated with the engine generator set governor and voltage regulator. These controls are supplied as part of the engine generator set for mounting and wiring by the switchboard manufacturer. Controls include but not be limited to:

(1)	Electronic control portion of governor.

(2)	Voltage regulator.

(3)	Motorized voltage adjust potentiometer.

(4)	Cross current compensation transformer.

(5)	Isolation transformer when required.

D.	Master control cubicle: Include the following basic components and any additional equipment necessary to provide for a complete and dependable system. All instruments shall be 4-1/2 in. switchboard type, 1 percent accuracy. Instrument control switches shall be heavy duty switchboard rotary type.

1.	Kilowatt load computer system:

a.	After a predetermined adjustable time delay, 0-30 minutes, a solid state kilowatt sensing system will be placed into operation to control the addition or subtraction of engines as required.

(1)	The kilowatt load sensing system shall be provided with separate increase and decrease load adjustments to accommodate the number of engines operating regardless of sequence.

(2)	The kilowatt monitoring system shall be provided with separate solid state sensors to monitor decrease load, increase load, and overload. Upon reaching the overload position, load relays will be energized and the next engine in line will be started immediately and synchronized to the bus.

2.	Load shedding and reading control panel.

a.	Load control relays shall be supplied in the master control cubicle with normally closed or open contacts for connection to the load shedding devices. Load shedding shall cease as soon as the overload sensor contacts have been reset. A lockout relay shall be supplied to prevent re-adding load until the automatic control system has had time to place another generator on the line. At the end of the timed period, the load shall be re-added in increments as determined by a time delay relay until power has been restored to all load circuits. Whenever the load control system is utilized, the station alarm system shall be energized to warn the operator that an overload condition has been experienced. A "Drop Low Priority Loads" pushbutton shall be supplied on the master control cubicle door for manual energization of the load control relays for the predetermined timed delay period. Provide annunciation only when load shed circuits are activated. Provide annunciation and switch for load shed bypass.

3.	Sequence plug system: to program starting and stopping sequence of units, including readout indicator showing numerical position of engine in system sequence.

4.	Manual paralleling permissive monitor (sync check) to prevent manual paralleling until both systems are within acceptable limits.

5.	Master control and synchronizing relay panel to control operation and synchronization of engine generators.

6.	Automatic DC control voltage sensor system to provide stable control voltage for switchboard.

NOTE: FOR PEAK LOAD SHAVING AND COGENERATION APPLICATIONS

7.	Station KWH meter with a 15 minute demand register, in a drawout case.

8.	Station power factor meter.

9.	Station ammeter with selector switch.

10.	Two position "Test-Normal" switch (key operated).

11.	Status lights showing number of "Engines Locked Out," "Engines Running"; "Engines 'closed to Bus".

12.	Station alarm horn with silencer switch and light (with "ring-back" provisions).

13.	Master "Auto-Manual" switch.

14.	Bus voltmeter selector switch, 7 position with voltmeter.

15.	Fail lights.

16.	Potential transformers as required.

17.	Current transformers, as required.

18.	Synchronizing swing panel.

a.	Bus AC voltmeter 0 - volt scale.

b.	Synchroscope.

c.	Selector switch.

d.	Synchronizing lamps.

e.	Frequency meter for station bus and generating units, dial type, 55 to 65 hertz scale.

f.	Watt/VAR meter.

19.	Fail circuitry:

a.	Low fuel day tank - alarm only.

b.	Low fuel main tank - alarm only.

c.	Over/under voltage - alarm only.

d.	Over frequency - alarm only.

e.	Under frequency overload - alarm and load shed.

20.	Control wiring, fuses, fuse blocks, terminals, nameplates, etc., as required. All wiring shall be numbered at both ends.

21.	Power management controller for peak load shaving.

a.	Purpose:

(1)	Sense and sum facilities total power requirement.

(2)	When the KW level supplied by the utility service exceeds a preset KW demand level for a time consistent with the utility d demand interval, a signal initiates the peak demand interval, a signal initiates the peak demand mode of operation as defined in the "Description of Operation" paragraphs of this section.

(3)	When the total load, that is the sum of the utility derived power, reduced to a level below the KW demand set point for an adjustable time delay, the peak demand controller initiates retransfer of the peaking loads an concludes the peak demand reduction mode operation.

b.	Visual alarm and contact signal: Initiated when the demand on the utility exceeds the KW demand set point for and adjustable time delay during the peak demand reduction mode.

c.	Includes:

(1)	KW demand setpoint - adjustable from 0 to ----- KW.

(2)	Time delay on transfer to the generator - adjustable 0 to 99 min.

(3)	Time delay on transfer to the utility - adjustable 0 to 99 min.

(4)	Peak demand mode time delay - adjustable 0 to 99 sec.

(5)	Control switch - three position key-operated switch to select "Manual," "Auto," and "Power Off" modes

(6)	Control inputs - shall accept four independent analog inputs of 0-1 MA for use with supplied KW transducers (current and potential transformers).

22.	Phase band monitor or synchronous check relay (devices).

a.	Purpose: compare phase angle of oncoming generators.

b.	Phase band monitor operating criteria: When the voltage and frequency limits are satisfied and the relative phase angle between the oncoming generator and bus reduces to 5 deg approaching zero deg, the circuit breaker closing relay will initiate breaker closing for paralleling. Paralleling to be inhibited unless voltage, frequency and relative phase angle are within preset limits at instant of paralleling.

c.	Synchronous check relay operating criteria: solid state, one shot reclosing, open interval 0 - 60 seconds, reset time 30 seconds fixed.

d.	Selector switch: for manual paralleling.

E.	Remote annunciator panel.

1.	Surface mounted, NEMA I enclosure with alarms in accordance with NFPA 76A-1977 requirements, and as listed below.

2.	Provide audible and visual signal to warn of derangement of alarm conditions. Pilot lights shall be press-to-test type. An audible alarm silencing switch shall be provided. A visual signal shall be provided for each engine generator, including future engine generators.

3.	Located as shown on drawings.

4.	Individual visual pilot lights (one set for each engine generator) and audible signals for the following:

a.	Low fuel oil level.

b.	Low lubricating oil pressure.

c.	Low water temperature.

d.	High water temperature.

e.	Overspeed shutdown.

f.	Overcrank shutdown.

g.	Battery charger malfunctioning (visual only).

h.	Generator supplying power to load (visual only).

5.	Nameplate for each item.

6.	Manufacturer: same as generator synchronizing switchboard.

7.	Include all necessary internal control wiring, terminal blocks, etc.

F.	Control wiring.

1.	Between actuating devices and generator synchronizing switchboard.

2.	Between automatic transfer switches and generator synchronizing switchboard.

3.	All other wiring required for successful operation of the system.

G.	Battery system:

1.	Self-contained free-standing console.

a.	Battery.

b.	Battery charger.

c.	Controls and indications.

2.	Operation.

a.	Automatic with the charger maintaining battery fully charged under all normal service conditions.

b.	Convection cooling.

c.	Console.

(1)	Front panel mounted DC voltmeter, D.C. ammeter, float charger indicator, and a high-rate charge indicator.

(2)	Potentiometer to adjust float charge voltage.

(3)	Potentiometer to adjust high rate voltage.

(4)	AC and DC fuses.

(5)	AC and DC failure alarm relay.

(6)	Automatic 24-hour timer: following and AC power failure longer than 8 - 12 seconds, timer shall automatically switch the charger to high - rate mode. After the preset interval the timer returns the battery to float charge.

(7)	Batteries.

(a)	Nickel cadmium alkaline type.

(b)	48 volts.

(c)	Sized for generator starting and circuit breaker control.

(d)	Constant potential, two-rate type, with a regulated output voltage stability of plus or minus 10 percent.

(e)	Input: 120 volts, 60 Hz, single phase, A.C.

(f)	Output: 48 volts D.C.

2)	BASE BID MANUFACTURERS

A.	Russelectric.

B.	Automatic Switch Company.

Part 3 -	EXECUTION

1)	INSTALLATION

A.	Mount on floor channels set in concrete pad.

B.	Refinish damaged or scratched surfaces and rub down board with approved polish.

C.	Provide 24 in. wide insulating mat in front of boards and in rear of free standing ones.

D.	Provide protective covering during construction.

E.	Tighten all bolted connections prior to energizing.

2)	TESTS

A.	Operational.

B.	Switchboard test: as described under low voltage distribution equipment

3)	Technical services during installation and test: At the construction site, provide the services of a competent, factory trained engineer employed by the manufacturer to technically supervise and participate during all of the adjustments and tests. Adjust and test in presence of owner's representative.

A.	Provide the services of a competent engineer to instruct the contractor and coordinate the installation of the generating units.

B.	Provide 2 days of instructions to personnel designated by the owner to operate the equipment.

C.	Be responsible for field installation tests such as proper phase sequence to insure proper installation of the synchronization switchgear by the contractor.

D.	Coordinate the tests as specified under "Diesel Standby Power Plant".

E.	Demonstrate that any engine generator set can start, operate at rated parameters and assume load within seven seconds after initiation of star signal, and that the balance of the engine generator sets will be synchronized, paralleled, and divide the load within 10 seconds after initiation of the start signal.

F.	Coordinate and demonstrate the proper functioning of the load priority system and the reassignment of load priority.

G.	Coordinate and demonstrate the proper functioning of the utility peak demand reduction operation.