“Constant speed drive”的意思、由来-开放百科全书

A constant speed drive (CSD) is a type of transmission that takes an input shaft rotating at a wide range of speeds, delivering this power to an output shaft that rotates at a constant speed, despite the varying input. They are used to drive mechanisms, typically electrical generators, that require a constant input speed.

The term is most commonly applied to hydraulic transmissions found on the accessory drives of gas turbine engines, such as aircraft jet engines. On modern aircraft, the CSD is often combined with a generator into a single unit known as an integrated drive generator (IDG).

Mechanism

CSDs are mainly used on airliner and military aircraft jet engines to drive the alternating current (AC) electrical generator. In order to produce the proper voltage at a constant AC frequency, usually three-phase 115 VAC at 400 Hz, an alternator needs to spin at a constant specific speed (typically 6,000 RPM for air-cooled generators).^[1] Since the jet engine gearbox speed varies from idle to full power, this creates the need for a constant speed drive (CSD). The CSD takes the variable speed output of the accessory drive gearbox and hydro-mechanically produces a constant output RPM.^[2]^[3]

Different systems have been used to control the alternator speed. Modern designs are mostly hydrokinetic, but early designs often took advantage of the bleed air available from the engines. Some of these were mostly mechanically powered, with an air turbine to provide a vernier speed adjustment. Others were purely turbine-driven.^[4]

Integrated drive generator

On aircraft such as the Airbus A310, Airbus A320 family, Airbus A320neo, Airbus A330,^[5] Airbus A330neo, Airbus A340,^[6] Boeing 737 Next Generation, 747, 757, 767 and 777, an integrated drive generator (IDG) is used.^[7] This unit is simply a CSD and an oil cooled generator inside the same case.^[8] Troubleshooting is simplified as this unit is the line-replaceable electrical generation unit on the engine.

Manufacturers

UTC Aerospace Systems (formerly Hamilton Sundstrand) is an American manufacturer of CSD and IDG units.

Alternatives

A variable-speed constant-frequency (VSCF) generator can be used to provide AC power using an electronic tap converter.

See also

References

1. ^{{cite web |url=http://www.angelfire.com/ct3/ctenning/electrical_essays/777elecpwr/777_design.html|title=Designing the 777 Electrical Power System|author=Carl Tenning|publisher=|accessdate=10 August 2015}}
2. ^{{cite web |url=http://www.k-makris.gr/AircraftComponents/CSD/C.S.D.htm|title=CSD|publisher=|accessdate=10 August 2015 |archive-url=https://web.archive.org/web/20100731084928/http://www.k-makris.gr/AircraftComponents/CSD/C.S.D.htm |archive-date=2010-07-31 |dead-url=yes}}
3. ^{{cite web |url=http://www.freepatentsonline.com/4310768.html|title=Constant speed drive – Rolls-Royce Limited|publisher=|accessdate=10 August 2015}}
4. ^{{Cite journal |title=Accessory Power – Constant speed drives and starters |journal=Flight International |date=16 September 1960 |pages=460–461 |url=https://www.flightglobal.com/pdfarchive/view/1960/1960%20-%201967.html}}
5. ^{{cite web|url=http://www.smartcockpit.com/aircraft-ressources/A330-Electrical.html|title=A330 Electrical|publisher=|accessdate=10 August 2015}}
6. ^{{cite web|url=http://www.smartcockpit.com/aircraft-ressources/FCOM_A340-Electrical.html|title=FCOM A340 Electrical|publisher=|accessdate=10 August 2015}}
7. ^{{Cite book |title=The Aircraft Gas Turbine Engine and its Operation |work=P&W Oper. Instr. 200 |author=Pratt & Whitney |authorlink=Pratt & Whitney |publisher=United Technologies Corporation |id=P&W 182408 |date=August 1988 |pages=3–45}}
8. ^{{cite web|url=http://www.freepatentsonline.com/7064455.html|title=Fixed frequency electrical generation system and corresponding control procedure – Airbus France|publisher=|accessdate=10 August 2015}}