TEMPEST MG SET:
Series GRF Guideform Specification
This specification covers the requirements for a motor-generator (M-G) set consisting of, but not limited to:
- Two Bearing, Low Slip Induction Motor
- Brushless, Two Bearing, Synchronous Generator /Brushless Exciter
- Flexible Maintenance Free Isolation Style Coupling Between the Motor And Generator
- Static Voltage Regulator
- Molded Case Input and Generator Circuit Breakers
- Reduced Current Starter (20 kW and larger)
- Motor Controls
- Generator Controls
- Skid-Base And Silencing Housing
- Integral EMP Choke and Lightning Arrestor
M-G sets 48KW and below shall be rated for three phase 480V/60Hz, 380V/50Hz & 208V/50 or 60Hz (Input or Output); and 0.8 power factor operation as follows:
- 60 kVA, 48 kW, 60 Hz / 50 kVA, 40 kW, 50 Hz
- 30 kVA, 24 kW, 60 Hz / 25 kVA, 20 kW, 50 Hz
- 12.5 kVA, 10 kW, 60 Hz / 10 kVA, 8 kW, 50 Hz
- 6.25 kVA, 5 kW, 60 Hz / 5 kVA, 4 kW, 50 Hz
- 312 kVA, 250 kW, 60 Hz / 250 kVA, 200 kW, 50 Hz
- 250 kVA, 200 kW, 60 Hz / 200 kVA, 160 kW, 50 Hz
- 218 kVA, 175 kW, 60 Hz / 175 kVA, 140 kW, 50 Hz
- 187 kVA, 150 kW, 60 Hz / 150 kVA, 125 kW, 50 Hz
- 150 kVA, 120 kW, 60 Hz / 125 kVA, 100 kW, 50 Hz
- 125 kVA, 100 kW, 60 Hz / 100 kVA, 80 kW, 50 Hz
- 94 kVA, 75 kW, 60 Hz / 75 kVA, 60 kW, 50 Hz
The motor-generator shall provide a means of electro-mechanically isolating and filtering disturbances in the AC source from the output of the generator. Generator Controls are separate and isolated from the Motor Controls.
The system output frequency shall be within 97% of the supplied input frequency (50Hz or 60Hz).
4.0 Design Approval:
The contractor shall provide to the Contracting Officer, or the Contracting Officer’s Representative (COR), a complete set of blue or black line design drawings describing the M-G set in sufficient detail to allow a decision as to the acceptability of the design. The drawings shall include:
- Overall Dimensions
- Location Of All Major Components
- One-Line Diagram
- Elevation and Customer Connections Details
5.0 General Requirements:
5.1 Environmental Characteristics:
- 0-95% non-condensing humidity’s with ambient temperatures ranging from + 0°C to + 40°C at sea level to 8,000 feet (de-rate 7% above 3200 ft).
- Rated for Interior of a building.
Adjustment, repair and replacement of all parts, assemblies and accessories shall be possible without disturbance to other elements of the M-G. Maintenance shall be possible using common tools. Maintenance shall be possible from one side and one end.
The M-G shall be capable of 24-hour continuous operation without routine visual checks, or any type maintenance, between recommended maintenance intervals.
All equipment specified herein shall comply with the safety requirements of NEMA MG-2. Exposed parts of such nature as to be a hazard to personnel shall be insulated, enclosed or guarded without impairing the functioning of these parts. Unused length of threads on studs, bolts, or screws shall not exceed the diameter of the stud, bolt or screw.
The M-G set shall be designed to operate for 50,000 hours without the required replacement of any part or component.
The number and type of individual parts and assemblies shall be maximized for the different rating.
5.6 Operating Speeds:
Rated speed of the M-G set shall be 1500 RPM for 50 Hz operation and 1800 RPM for 60 Hz operation.
The base assembly shall be fabricated from ASTM A-36 standard structural steel shapes. It shall be sufficiently rigid to ensure permanent alignment of the motor and generator during handling and shipping. The base shall include mounting holes for vibration isolators. All equipment shall be mounted so as not to extend beyond the outer edges of the base. The base shall be constructed with lifting attachments so that the M-G set can be lifted without damage to any part.
5.8 Sound Enclosure:
A sound enclosure split into at least two sections shall be provided to reduce the noise at two meters from M-G set to:
- 72 dBA for system smaller than 50kW
- 82 dBA for systems greater than 50kW
All materials, components and parts shall be new and standard production items. All items such as bolts, screws, nuts, and washers shall be of an approved corrosion-resistant material or shall be suitably treated to resist corrosion. The number of different sizes and types of hardware shall be kept to a minimum.
5.9.1 Corrosion-Resistant Materials:
The following are the only acceptable corrosion-resistant metals (as distinguished from corrosion-resisting treatments):
- Corrosion-Resisting Steel, with chromium
- Alloys of Copper & Nickel
Uniform coating of a sufficient thickness of chromium, copper, silver or zinc are approved corrosion-resistant treatments.
5.9.3 Thermal & Sound Insulating Materials:
Thermal and sound insulating material shall have a continuous service minimum temperature rating of 80°C (175°F) and a minimum service temperature rating of -43°C (-45°F) to 107°C (225°F) and shall meet the following specifications:
- Heat Resistance: ASTM D3574-77, Test K
- Humidity Resistance: ASTM D3574-77, Test J and SCTM #FM-R05
- Flame Resistance*: UL Recognized as UL 94 HF-1
- Meets MVSS-302
- Meets FAR 25.853 (b) Vertical Burning Test
5.9.4 Dissimilar Metals:
Contact between dissimilar metals, which could cause deterioration of parts by galvanic action, shall be avoided whenever possible. If contact between dissimilar metals cannot be avoided, the surfaces shall be treated.
Cleaning, painting, plating anodic films, and chemical treatment shall be in accordance with the manufacturer’s/contractor’s standard practices.
Push-button switches shall be UL recognized components. They shall have screw type terminals suitable for accepting #16 AWG wire.
Relays shall be the plug-in type with dust cover.
5.9.8 Resistors & Rheostats:
Power resistors shall be wire wound. Where adjustable resistors are used, tapped resistors shall be used in lieu of slide type. All rheostats and potentiometers shall be of the wire wound type.
5.9.9 Hinges & Latches:
Hinges and movable parts of latches shall be made of corrosion-resistant material. Provisions shall be made to prevent hinge pins from being removed when doors are installed.
126.96.36.199 Non Electrical:
Each fastener shall be equipped with a suitable locking device to prevent loosening due to vibration. Locking shall be by locknut, castellated nuts with cotter pins, lock washers, self-locking nuts, lock wire or lock plate.
Locking devices shall be used for each fastener used in making an electrical connection except for the screws furnished with components. Fasteners shall not be depended on to carry current; they shall serve to hold current carrying parts in contact with each other. Where flow of current through a stud cannot be avoided, the stud and all associated hardware shall be made of corrosion-resistant material. Unused length of threads shall not exceed half the diameter of the stud.
5.9.11 Terminal Strips & Terminal Supports:
Terminal strips shall be of sufficient size to accommodate the ringed terminal lugs used on #16 AWG wire or be of the type that accepts non terminated stranded wire.
The instrument transformers shall be 600 volt insulation class. Instrument transformers shall conform to ANSI C57.13. The accuracy class burden rating shall be 2%.
Shunts shall conform to MIL-S-61.
All wire shall be with type suitable for the application. All conductors shall be identified at both ends within two inches of the connection point and so referenced on the drawings. Wire markers shall be of thermally labeled heat shrinkable type. For terminal blocks requiring wire lugs, pressure-type, insulated barrel ring lugs, which grip the insulation as well as the wire conductors, shall be used. A constant-pressure crimping tool, which performs both crimps simultaneously, must be used. No solder connections shall be used except on potentiometer. No wire smaller than #16 AWG shall be used.
The working voltage of capacitors shall be at least twice the maximum operating voltage.
Switches shall be UL recognized components. They shall have screw type terminals suitable for accepting #14 AWG wire. All switches shall be flush with the enclosure to decrease damage occurring to them.
5.9.17 Printed Circuit Boards:
Printed circuit boards shall not be used unless provided as components of specified assemblies.
188.8.131.52 Semiconductor Devices:
All semiconductor devices shall be of the hermetically sealed silicon type, and have a PIV (Peak Inverse Voltage) rating equal to or greater than twice the maximum operation voltage.
184.108.40.206 Fungus & Moisture Resistance:
The electrical circuitry, including all components and connections, except as specified below, shall be protected from the effects of fungus growth and moisture by treatment with a varnish:
- Components or circuit elements that are inherently fungus and moisture resistant or which are hermetically sealed.
- Components or circuit elements whose function will be affected by the varnish coating.
6.0 Motor & Generator:
The bearings shall be a sealed grease-lubricated, anti-friction type.
6.2 Mechanical Vibration:
The motor and generator shall be balanced in accordance with NEMA MG-1. When operating at rated speed and voltage, and at any load from no load to rated load, the vibration amplitude, peak-to-peak, shall not exceed the value as specified in NEMA MG-1 for the rated speed of the M-G set. The vibration amplitude shall be measured in all three axes (vertical, longitudinal and transverse) at the bearing housing or on the frame adjacent to the bearing housing.
6.3 Temperature Rise:
Allowable temperature rise of coils, windings and mechanical parts, when the M-G and auxiliary items are installed shall not exceed the following:
- Coils, windings and connections as measured: 105°C
- Generator bearings: 50°C
- Poles, cores and other mechanical parts in: 105°C
6.4 Dielectric Strength:
Windings shall withstand the following 60 Hz voltages applied for one minute:
- Generator field and exciter windings - 10 times ceiling voltage, but neither less than 1,500 nor more than 3,500 volts (applied between windings and ground).
- All others –85% of, twice rated voltage plus 1,000 volts (applied between winding and ground, and between windings where applicable).
The motor shall be such that the output frequency shall maintain a minimum of 97% of input frequency. In addition, the motor shall be two bearing, air-cooled, self-ventilated induction type connected to the generator through a flexible coupling. The motor shall be rated for both 50 Hz and 60 Hz operation; it shall have power leads, each sufficiently long to allow easy connection of the individual phase coil in series or parallel. The windings shall be copper.
The AC generator shall be a synchronous, revolving field, brushless, two bearing, air-cooled, self-ventilated alternator, which is driven by the motor through a flexible coupling. The generator shall be rated for both 50 Hz and 60 Hz operation; it shall have power leads, sufficiently long to allow easy connection of the individual phase coil in series or parallel. The generator shall conform to the applicable requirements of ANSI C50.10, and NEMA MG-1. The generator windings shall be copper. The balanced and residual component telephone influence factor (TIF) shall not exceed the values specified in NEMA MG-1. The generator shall have amortisseur windings for paralleling.
9.0 Excitation System:
The excitation system shall consist of an exciter and voltage regulator.
The generator exciter shall be a rotating, brushless type with a rectifier assembly integral with the main generator. The rotating rectifier assemblies shall be mounted in a manner to provide ready access for inspection and replacement of rectifier diodes.
The voltage regulator shall be of the solid-state type and shall control the generator field current automatically through action on the exciter. The voltage regulator shall have provisions for manual adjustment of the generator output voltage while the M-G set is in operation via a voltage adjusting control.
10.0 Performance Requirements:
The motor and generator shall not exceed the temperature rise in paragraph 6.3 when the M-G set is operating in any ambient temperatures specified herein under the following:
10.3 Phase Sequence Rotation:
Phase rotation at the M-G set output terminals shall be A, B and C when the M-G set is rotating in the indicated direction.
The voltage regulation from no load to rated load and from rated load to no load shall be not more than 1% of rated voltage.
10.5 Short-Term Stability (30 seconds):
At every constant load from no load to rated load, the voltage at the output terminals shall remain within a bandwidth equal to 1% of rated voltage.
10.6 Long-Term Stability (4 hours):
At constant ambient temperature, constant atmospheric pressure, constant input frequency, and any constant load from no load to rated load, the voltage at the output terminals shall remain within a bandwidth of 2% of rated voltage in a 4 hour operating period.
When operating at constant load and frequency, a change in ambient temperature up to 60°F in an 8 hour period shall not cause the voltage at the output terminals to change by more than 1%, temperature stabilization being accomplished at both the initial and final ambient temperature conditions.
10.8 Transient Performance:
The transient performance shall be measured by an oscillograph.
- With the M-G set initially operating at no load, rated voltage and rated frequency, the instantaneous terminal voltage of the generator shall not drop to less than 70% of the no load voltage when a balanced three phase, 0.8 power factor lagging, static load having an impedance of 0.5 per unit is suddenly applied to the output terminals of the generator. When connected to the specified load, the output voltage shall recover to a minimum of 95% of rated voltage within 0.7 seconds and shall stabilize at 95% - 100% rated voltage.
- With the M-G set initially operating at no load, rated frequency, rated voltage, and following any sudden change in load from no load to rated load, the instantaneous voltage shall not drop to less than 80% of rated voltage and shall reach stable conditions within 0.8 seconds; no overshoot or undershoot of the final voltage may exceed the initial voltage transient in amplitude. The above requirements shall also apply when load is suddenly changed from rated load to no load, except that the initial voltage transient shall not exceed 120% of rated voltage.
10.9 Adjustment Range:
The line-to-neutral output voltage shall be adjustable to any value within a range of ± 10% at 50 Hz and 60 Hz.
The deviation factor for the generator line-to-line and line-to-neutral voltage waveform for each voltage connection shall not be more than 5%, nor shall any single voltage harmonic be more than 3%. In addition, there shall be no evident discontinuities, spikes, or notches in the waveform when viewed on an oscilloscope having a bandwidth of DC to 20 MHz and a usable viewing screen of 8 x 10 cm. The oscilloscope gain shall be adjusted such that one cycle of voltage wave covers approximately the entire viewing screen.
10.11 Voltage Balance w/Unbalanced Load:
When operating at rated voltage and frequency, maximum difference between the generator line-to-line voltages shall not be more than 5% of rated voltage under the condition of a single phase, line-to-line unity PF-load of 25% of rated current and no other load on the generator.
10.12 Phase Balance Voltage:
The maximum difference in the generator three line-to-neutral voltages shall not be more than 1% of rated line-to-neutral voltage. The maximum difference between the voltage of the 120 volt windings of any one phase shall be not more than 1 volt.
10.13 Motor Starting Current:
The starting current shall not exceed three times the nameplate current.
The M-G set shall not be damaged and the generator output voltage shall remain within a bandwidth equal to 1% of rated voltage when the input voltage to the motor is between 110% and 85% of rated value.
10.15 Voltage Sag:
The M-G set shall not be damaged and the generator output contactor shall not open when the input voltage to the motor is reduced to 80% of rated value for 30 seconds or less.
10.16 Voltage Impulse:
The M-G set shall not be damaged when the input voltage to the motor is increased to 1500 volts for 1 millisecond.
The control circuit shall provide for the automatic restarting of the M-G set after a power failure. Automatic Restart shall be enabled by a control switch.
All AC electrical components of the motor and generator shall be isolated from ground, except as otherwise specified herein. The motor frame shall be isolated from the base assembly and be equipped with an input ground connection that can be used to ground the motor. The generator frame shall be isolated from the base assembly and provided with an output ground connection that can be used to ground the generator. The frame shall be provided with ground studs that can be customer selected to ground either the input/motor or the output/generator to the frame.
12.0 Motor/Generator Coupling:
The motor and generator shall be directly connected by a flexible, non electrically conducting maintenance free style coupling.
13.0 Instruments & Controls:
13.1 Control Cubicle:
A NEMA 1 M-G set control cubicle(s) shall be provided that incorporates complete controls for all functions of the M-G set. The cubicle(s) shall have a hinged door. The door panel shall open outward. The door shall open at least 90 degrees and shall have provisions to limit travel to prevent damage to panel mounted instruments and controls. The cubicle(s) shall contain all necessary control circuit breakers, controls, relays, timers, resistors, switches, push-buttons, lamps, instruments, governor, etc., to control the M-G as specified in this specification. All components shall be accessible from the front of the control cubicle. The protection for control circuit(s), except for the lightening arrestor, shall use circuit breakers in lieu of fuses. The following items shall be mounted on the control panel(s):
13.1.1 AC Voltmeter:
The voltmeter shall be a 600 volt, single scale, semi-flush mounted type, 2 ½ “, 2% accuracy. Instrument dial shall be of contrasting background with marking to ensure legibility. This meter shall be identified as “AC Volts”. Meter meets ANSI Specifications C-39.1
13.1.2 AC Ammeter:
The ammeter shall be a single scale, semi-flush mounted type, 2 ½”, 2% accuracy. Instrument dial shall be of contrasting background with marking to ensure legibility. This meter shall be identified as “AC Amps”. Meter meets ANSI Specifications C-39.1
13.1.3 Selector Switch:
A combination voltmeter/ammeter selector switch is preferable. If other requirements dictate, separate voltmeter/ammeter selector switch can be used for the motor input and the generator output.
220.127.116.11 Voltmeter/Ammeter Selector Switch:
If a combination ammeter/voltmeter selector switch is provided, it shall allow measurement of currents and voltages at the input side of the motor after the input circuit breaker and the output of the generator before the output contactor. Contacts shall be arranged so that current transformer secondaries are never open circuited when switching from one position to another. This switch shall be identified as “Ammeter-Voltmeter” and the ammeter and voltmeter indications for various positions of the switch shall be as follows:
If two ammeter/voltmeter selector switches are provided, they shall allow measurement of currents and voltages at the input side of the motor after the input circuit breaker and the output of the generator before the output contactor. Contacts shall be arranged so that current transformer secondaries are never open circuited when switching from one position to another. This switch shall be identified as “Input Ammeter –Voltmeter” and “Output Ammeter - Voltmeter” and the ammeter and voltmeter indications for various positions of the switch shall be as follows:
The frequency meter shall monitor the motor input and shall be a single scale, semi-flush mounted type, 2 ½”, 2% accuracy. Instrument dial shall be of contrasting background with marking to ensure legibility. The scale shall be 45 Hz to 65 Hz. Meter meets ANSI Specifications C-39.1
A 10-turn rheostat shall be provided to adjust the output voltage. The rheostat shall be identified as “Generator Volts Adjust”.
All push-buttons shall meet the following standards:
Flammability UL94V-0 (housing and base), UL & C-UL Recognized and CSA certified.
18.104.22.168 Motor Start:
A green push-button shall be provided to start the M-G set through the motor starter.
22.214.171.124 Motor Stop:
A red push-button shall be provided to stop the M-G set.
126.96.36.199 Output On:
A green push-button shall be used to close the generator output contactor.
188.8.131.52 Output Off:
A red push-button shall be provided to open the generator output contactor.
184.108.40.206 Emergency Stop:
A switch, protected from accidental use, shall be provided to stop the M-G set and simultaneously open the generator output circuit breaker.
13.1.7 Status Lights:
There shall be LED lamp holders as follows:
- A holder with a red lens shall be labeled “Low Input Volts” and shall illuminate when the input power is not suitable to start the motor.
- A holder with a green lens shall be labeled “Motor On” and illuminate when the motor is running.
- A holder with a green lens shall be labeled “Output On” and should illuminate when the output contactor is closed and output power is available.
- Holders with red lenses shall be labeled “with specific faults” and shall illuminate when the faults occur. The light shall stay on until the fault is cleared.
An AC input circuit breaker shall be mounted on the motor end of the M-G set and shall have instantaneous short circuit trip and auxiliary contacts as required. The circuit breaker shall connect the M-G set to the input power.
13.3 Input Voltage Monitor:
A voltage monitor shall be connected to the output side of the AC input circuit breaker and shall provide a closed contact that will allow starting of the motor only when all three phase are within allowable limits. Opening of the contact after the M-G Set is operating shall not stop the M-G Set.
13.4 Motor Starter:
The motor starter shall be activated by the start push-button when the source voltage within the allowable limit. Units 24 kW and larger shall start the motor through the current limiting device that limits the current to less than three times the nameplate current. The starter shall transfer to normal position through a time delay.
13.5 Output Contactor:
The generator output contactor shall be controlled by the load push-button and shall connect the output of the generator to the load when the voltage and frequency are within allowable limits.
13.6 Remote EPO Switch:
Provision shall be made to permit emergency shutdown by the connection of a normally closed, 5 ampere remote “Emergency Power Off” switch located up to 50 feet from the unit.
13.7 Remote Fault Indication Relay:
The system shall be equipped with a 5 amp, normally open contact that activates when a fault occurs. These contacts will be used for signaling purposes.
14.0 Protective Devices:
14.1 Motor Starter:
The motor starter shall be provided with a thermal protective device that will stop the motor and activate a fault indicator when the individual phase current exceeds the allowable limit. If protective devices are required for the different input voltages, they shall be shipped with the unit.
The M-G set shall be equipped with a protective device that opens the generator contactor, activates the fault indicators, and locks out the remaining fault indicators. The indicator shall retain the fault indication after the unit has stopped. Reset shall be required before restart.
The overvoltage protective device shall actuate after the generator voltage has risen to any value greater than 110% of rated generator output voltage. The relay shall have a time delay that will prevent tripping during transients, which are within the limits of this specification (paragraph 10.9).
The undervoltage protective device shall activate when the generator voltage has fallen to 90% of rated generator output voltage. The relay shall have a time delay that will prevent tripping during transients, which are within the limits of this specification (paragraph 10.9).
The underfrequency protective device shall activate when the generator output frequency decreases to more than 5 Hz of rated frequency. Provision shall be provided for selecting 50 Hz or 60 Hz operation.
The motor overload protective device shall activate when a motor overload occurs. The device shall stop the unit, simultaneously open the motor contactor, activate the fault indicators, and lock out the remaining fault indicators. The indicator shall retain the fault indication after the unit has stopped. Reset shall be required before restart. The overload shall not trip during overloads specified in paragraph 10.1. If thermal protective devices are required for different input voltage ratings, they shall be shipped with the unit.
14.4 Motor & Generator Enclosure Overtemperature:
The motor and generator enclosure overtemperature protective device shall activate when an enclosure temperature exceeds a preset value. The device shall open the generator contactor, stop the motor, activate the fault indicators, and lock out the remaining fault indicators. The indicator shall retain the fault indication after the unit has stopped. Reset shall be required before restart.
5.0 Factory Testing:
15.1 M-G Set:
The following tests shall be conducted on the complete M-G set. During these tests, the M-G set input shall be at rated voltage and frequency.
- Contractors M-G’s Checkout
- Initial Test Run - An initial start-up and run test of the M-G set shall be performed by the contractor prior to presenting the M-G set for official testing. During this test, all operating conditions shall be verified as being within normal operating parameters and recorded on the test form. The M-G set should be visually checked during this brief initial run test for any evidence of noise or similar abnormal operating conditions.
- Output Frequency - The output frequency at no load and rated load shall be verified as being within limits.
- Voltage Control - After confirmation that the M-G set is operating at the proper frequency, the voltage regulator output voltage shall be set to the specified output voltage. Confirmation should be made that the voltage adjust rheostat is at the mid-point of its range with the M-G set operating at the specified output voltage.
- Tests shall be performed by the contractor to document compliance with the following requirements using a contractor prepared and COR approved test plan. All load tests shall be conducted at 1.0 PF.