6b_m3_c3

GGGEEE EEEnnneeerrrgggyyy PPPrrroooddduuuccctttsss ––– EEEuuurrrooopppeee OPERATION AND MAINTENANCE GUIDE Rev : A Page : 1/2

DESCRIPTIVE GUIDE

All right reserved Copyright – Droits de reproduction réservés 6bev_m3_c3_p1 opt 1.6.doc Revision : A Date : 04/06

3.3. STARTING SYSTEM

3.3.1. GENERAL AND SIMPLIFIED SCHEMATIC

Before the gas turbine can be fired and started it must be rotated or cranked by the accessory equipment. This is accomplished by a starting engine, operating through a torque converter to provide the cranking torque required by the turbine for start-up. Starting system components include : The starting engine, torque converter with ratchetting mechanism, starting jaw clutch and a hydraulic ratchet system. (See the sketch here after, Figure SS-1.) In addition, there are several supplementary components required for sequencing and operation of the turbine starting system. These are included in the descriptive system text that follows. During the starting sequence, the gas turbine is driven through the accessory gear by the starting engine, torque converter, output gear, and the starting clutch. The starting clutch assembly and the engagement cylinders are mounted on the accessory gear assembly. The accessory gear is permanently coupled to the turbine compressor shaft by a coupling. The accessory gear drives the main lube pump, main hydraulic supply pump, cooling water pump (and, when a liquid fuel is used, the atomizing air compressor and the main fuel pump).


DESCRIPTIVE GUIDE


FIG

UR

E SS

-1 :

STA

RTI

NG

SYS

TEM

SC

HEM

ATI

C

AC

CES

SOR

Y G

EAR

TO G

AS

TUR

BIN

E C

OM

PRES

SOR

SH

AFT

JAW

C

LUTC

H

MU

FFLE

R

AIR

INW

F

WR

VAR

IAB

LE

SPEE

D

GO

VER

NO

R

34D

C

88D

S

ELEC

TRIC

STA

RT

MO

TOR

SMD

STA

RTI

NG

D

IESE

L

FOO

TVA

LVE

OIL

SUM

PCH

ECK

VA

LVE

HM

1 T

OR

QU

E C

ON

VER

TER

W

ITH

INTE

GR

AL

RA

TCH

ET

WF

– W

ATE

R F

EED

W

R –

WA

TER

RET

UR

N

DO

L–

DIE

SEL

LUB

EO

IL


DESCRIPTIVE GUIDE


3.3.2. DIESEL ENGINE

When operating, the diesel engine draws combustion air from the accessory compartment through a filter into the turbo-charger inlets. Airs dampers, located downstream of the turbo-chargers, are equipped with a manual emergency shutdown latch. Engine coolant is drawn from the gas turbine cooling water system tank located on the accessory compartment roof. The flow rate is controlled by thermostats on the engine. The engine operates on a completely self-contained lube oil system. Lube oil pressure is monitored by the regulator 34 DC. A fuel tank has been fabricated in the turbine base. Refilling of this tank is a manual operation. Refer to the engine operators manual for the specifications of acceptable fuels. CAUTION : Operation on fuels other than clean, dry, diesel fuel, as per engine

manufacturers recommendations, can result in severe damage to the engine.

An engine driven, high lift pump draws fuel from the tank and pumps it through a filter to the cannister mounted on the side of the engine. The main fuel pump draws fuel from the cannister and pumps it through a filter and into the injector headers. Each fuel injector draws the required amount of fuel from the headers, while the excess fuel (used to cool the injectors) is returned to the cannister and through the overflow drain, back to the tank. There is a manual ”priming” pump installed in parallel with the high lift pump. CAUTION : Attempting to ”prime” the engine fuel system by cranking the engine can

seriously affect the life of the engine starter.

Diesel engine controls The basic control elements include a starter, speed control system, stop mechanism, and electronic logic in the gas turbine control panel for unattended, automatic protection and control. Engine starter 88 DS is a direct current motor that engages with the engine through a Bendix drive. Engine speed is controlled by the regulator 34 DC by the SPEEDTRONIC. Electronic logic in the control panel provides automatic sequencing for normal unit startup, for normal and emergency engine shutdown and for exercising and/or test of the engine. To protect the system hardware, the logic also monitors the starting clutch position (33 CS-1), the engine lube oil pressure and the engine speed and ALARMS or ALARM/TRIPS as necessary. Diesel engine operation After the starting clutch is engaged, 88 DS-1 is energized to start the engine. The engine idles through the warmup cycle and accelerates the engine to maximum speed for unit breakaway (requires assistance of the hydraulic ratchet). Following breakaway decelerate the engine to approximately 1900 rpm at which point to hold constant engine speed until the gas turbine is sequenced through the end of warmup. The engine back to maximum speed (and power) for acceleration of the unit to speed of about 3100 and 3200 rpm, the clutch automatically disengages. The engine returns to idle speed, idles through a cooldown period.


DESCRIPTIVE GUIDE


PART 4 DDEC 5 DE 30 DE 34 DC 43 DE 77 DE 88 DS 90 DE 94 DE CS 1 HM 1 SMD VR 23 VPR 38

NOMENCLATURE Diesel start. Push button in case of emergency. Diesel start alarm relay. Diesel control sequencer. Diesel engine control switch. Diesel speed signal (display only). Diesel (starting) engine starter. Diesel speed control set point. Diesel trip relay. Starting jaw clutch. Torque converter and reversing gear. Diesel engine. Torque converter charge pump pressure relief valve. Torque converter charge pump primer valve.


DESCRIPTIVE GUIDE


STA

RTI

NG

MEA

NS

(DIE

SEL

ENG

INE)

SC

HEM

ATI

C


DESCRIPTIVE GUIDE


3.3.3. TORQUE CONVERTER AND HYDRAULIC RATCHET ASSEMBLY

This assembly includes the torque converter, the hydraulic ratchet mechanism and an output gear unit. In case of diesel starting engine, it is mounted on the diesel engine fly wheel housing. A small engine driven pump supplies turbine lube oil to the torque converter loop during engine operation. The loop is pressurized by an orifice in the discharge port. The gear unit and the clutch in the ratchet mechanism are lubricated by pressurized oil from the converter loop. Drain oil from the assembly returns to the turbine sump by gravity and the converter loop drains during shut down to unload the converter for engine start-up. Refer to Figure SS-2 here after. • The torque converter consists of an engine driven pump rotor that supplies oil to a

hydraulic turbine connected to the input shaft of the output gear. The pump rotor requires rated engine horsepower at rated speed, independent of the output load. Power absorption of the pump rotor varies as the cube of the input speed.

In the system, the valve module controls the starting clutch engagement and the hydraulic self-sequencing operation of the rotary actuator. The module includes the ON/OFF solenoid valve 20 CS-1, the modulating back pressure valve that maintains adequate pressure to the clutch engagement cylinders, two pilot operated valves to control flow to the rotary actuator, and the 33 HR limit switch. A motor and pump assembly pumps lube oil from the unit bearing header to the inlets of the VR 5 relief valve and the control valve module. CAUTION Setting relief valve VR5 at a ”cracking” pressure above 1350 psig (i.e. about 93

bars) can damage the one way clutch in the ratchet mechanism. Check the setting in the Device Summary, Gas turbine operation guide volumes.

Ratchet system operation With the pump PH 3 in operation and solenoid valve 20 CS-1 energized, oil from the lubrication system is ported to the starting clutch. This causes the ratchet mechanism to operate continuously as the hydraulic self-sequencing control automatically shifts the oil flow between the forward and reset strokes of the ratchet mechanism. A forward stroke advances the starting clutch about 47 degrees during the 10 seconds duration. The reset stroke is about 4.5 seconds duration. Operation for unit cooldown is automatically sequenced by the electronic control panel. Once every three minutes, the mechanism is operated through one complete cycle. The cycle is terminated in the forward stroke position to lock the clutch in the engaged position. Ratchet operation is normally required to achieve breakaway of the unit rotor system during the unit start-up sequence. With the starting system at maximum power, 88 HR and 20 CS-1 are energized for continuous operation until breakaway is achieved. The ratchet system can also be manually operated by use of ”jog” switch 43 HR-1 located in the accessory compartment. Actuation of the ”jog” switch interrupts and terminates operation in any automatic sequence. Switch actuation energizes 88 HR-1 and 20 CS-1 and maintains both in an energized state as long as switch contact is maintained. Release of the switch immediately deenergizes both 88 HR and 20 CS-1 independent of the ratchet stroke position.


DESCRIPTIVE GUIDE


CAUTION Operation of the ratchet system without oil pressure in the gas turbine bearing header may damage the ratchet pump and/or the gas turbine bearings. Excessive continuous ratchet operation and/or jogging (”inching the rotor”) by use of the ”jog” switch can seriously affect the life of 88 HR and/or 20 CS-1.

• Starting jaw clutch CS1

A starting clutch connects the output shaft of the torque converter assembly to the main shaft of the accessory gear. The clutch is engaged by hydraulic cylinders (oil supplied from the ratchet control valve module) and disengaged by return springs in the cylinders. Engagement is maintained by transmitted torque generated in the torque converter and/or ratchet mechanism. Because of the one way clutch in the ratchet mechanism, the sliding clutch hub cannot be turned backwards except during a reset stroke of the ratchet mechanism. The system is designed to maintain the clutch in the engaged position at all times except when the gas turbine is running. To allow inspection and maintenance of the clutch mechanism, manual valve VM 2 has been installed in the hydraulic lines between the ratchet control module and the clutch cylinders. To disengage the clutch, shift the valve and operate the ratchet with the ”jog” switch ; the clutch will disengage during the ratchet reset stroke. Starting clutch operation is automatically controlled through the ratchet control valve module by the electronic control panel. The panel also includes adequate protection against any component malfunction or failure.


DESCRIPTIVE GUIDE


SHEET LEFT BLANK INTENTIONALLY


DESCRIPTIVE GUIDE


PART 20 CS-1 33 CS-1 33 HR 43 HR-1 88 HR CS 1 FH 1 FH 5 HM 2 PH 3 VH 14 VM 2 VR 5

NOMENCLATURE Starting clutch solenoid (part of VH 14). Starting clutch limit switch. Hydraulic ratchet limit switch. Hydraulic ratchet control switch. Hydraulic ratchet pump motor. Starting jaw clutch. Hydraulic ratchet supply filter. Ratchet pump hydraulic supply filter. Hydraulic ratchet mechanism. Hydraulic ratchet pump assembly. Hydraulic self-sequencing valve ratchet and clutch. Clutch disengagement manual 4-way valve. Hydraulic ratchet pump pressure relief valve.


DESCRIPTIVE GUIDE


FIGURE SS-2 : STARTING SYSTEM SCHEMATIC

6b_m3_c3

Documents

Transcript of 6b_m3_c3