DOM MANUAL / B-TECH / MECHANICAL / KUK - TO FIND THE SPEED AND TORQUE OF DIFFERENT GEARS IN AN EPICYCLIC GEAR TRAIN.

OBJECTIVE: TO FIND THE SPEED AND TORQUE OF DIFFERENT GEARS IN AN EPICYCLIC GEAR TRAIN.

SPECIFICATIONS:

1.      GEAR TRAIN : SUN GEAR : 14 TEETH

2.      PLANT GEAR: 21 TEETH (2 NOS.)

3.      INTERNAL GEAR WITH : 56 TEETH

TORQUE MEASUREMENT

·         INPUT TORQUE – MOTOR CURRENT CALIBRATED FOR MOTOR TORQUE.

·         PLANT CARRIER - PULLEY OF 50 MM DIA AND SPRING BALANCE.

·         INTERNAL GEAR - PULLEY, 120 MM DIA AND SPRING BALANCES.

Ø  BOTH PULLEYS ARE PROVIDED WITH ROPE OF 12

Ø  MM DIA

Ø  DRIVE MOTOR - 1HP DC MOTOR RPM MOTOR OPERATING ON 220 VOLTS

Ø  50 HZ SUPLLY, DRIVING THE SUN GEAR.

CURRENT(AMPS)	TORQUE
1.00	0.5
1.20	1.5
1.40	2.5
1.60	3.0
1.80	4.0
2.00	5.0
2.20	6.0

MOTOR CALIBRATION CHART

THEORY:

WHENEVER THE DISTANCE BETWEEN THE DRIVING AND DRIVEN MEMBER, (BOTH SHAFTS ARE NOT OPERATING ON THE SAME AXIS) IS SMALL OR WHEN A POSITIVE SLIP LESS DRIVE IS REQUIRED, GEAR DRIVES ARE USED .SUCH A COMBINATION OF TWO OR MORE GEARS IS CALLED GEAR TRAIN .GEAR TRAINS MAY BE SIMPLE, COMPOUND OR EPICYCLIC GEAR TRAINS .THE AXIS OF GEARS HAVE FIXED POSITION RELATIVE TO EACH OTHER. BUT IN EPICYCLIC GEAR TRAINS, THE AXIS OF GEARS MAY HAVE RELATIVE MOTION TO EACH OTHER.

THE APPARATUS CONSIST OF SUN AND PLANET GEAR TYPE EPICYCLIC GEAR TRAIN .A DRIVING MOTOR DRIVES THE SUN WHEEL. THE PLANATORY GEARS, WHICH MESH WITH THE SUN GEAR AND MOUNTED ON PINS, WHICH ARE FITTED TO PLANET CARRIERS PULLEY .EXTERNALLY, PLANET GEAR MESH WITH THE INTERNAL GEAR WHICH IS MOUNTED OVER A SHAFT .THIS SHAFT ALSO CARRIES A PULLEY. BOTH PULLIES ARE PROVIDED WITH ROPE BRAKE WITH SPRING BALANCES, SO THAT EITHER PLANET CARRIES PULLEY OR INTERNAL GEAR PULLEY CAN BE HELD STATIONARY AND OUTPUT TORQUE WITH HOLDING TORQUE CAN BE MEASURED .INPUT TORQUE HAS BEEN CALIBRATED IN TERMS OF MOTOR CURRENT.

PROCEDURE

Ø  CHECK THE NUT BOLTS FOR TIGHTENING (NORMALLY ALL NUT-BOLTS ARE TIGHTENED) CONNECT THE ELECTRICAL SUPPLY TO THE UNIT AND START THE UNIT.

Ø  TIGHTEN THE ROPE ON PLANET CARRIER PULLEY SO THAT IT DOSE NOT ROTATE. NOW, SLIGHTLY TIGHTEN THE ROPE OVER INTERNAL GEAR PULLEY.

Ø  NOTE DOWN THE OBSERVATIONS. REPEAT THE PROCEDURE FOR DIFFERENT TORQUES.

(NOTE: WHEN ROPE ON INTERNAL GEAR PULLEY IS TIGHTENED, PLANET CARRIER STARTS ROTATING. KEEP THE TENSION OF THE ROPE OVER THE PULLEY (INTERNAL GEAR PULLEY) SO THAT IT JUST DOSE NOT ROTATE)

Ø  NOW, HOLD THE CARRIER PULLEY AND LET INTERNAL GEAR PULLEY TO ROTATE.

Ø  REPEAT THE SAME PROCEDURE FOR DIFFERENT TORQUES AND COMPLETE THE OBSERVATION TABLE.

CALCULATIONS

·         LET US CALCULATE THE SPEED RATIO, USING TABULAR METHOD.

·         ASSUME PLANET CARRIER ‘C’ LOCKED AND SUN GEAR GIVEN ONE REVOLUTION.

S. NO.	OPERATION	PLANET CARRIER C	SUN GEAR S  14	PLANET GEAR P 21	INTERNAL GEAR I 156
01.	PLANET CARRIER LOCKED SUN GEAR GIVEN 1 ROTATION	0	+1	-TS --------- TP	-TS TP      -TS  ---   ---   = ----- TP T1         T1
02.	MULTIPLY BY ‘X’	0	X	-TS --------- X TP	-TS -------- X T1
03.	ADD ‘Y’ TO ALL COLUMNS	0	Y + X	Y -(TS/TP) X	Y - (TS/T1) X

1.     













       CONDITION 1 (PLANET CARRIER LOCKED)

IN THIS CONDITION, INTERNAL GEAR MAKES [-(TS T1) X] REVOLUTIONS OF SUN GEAR.

HENCE, ANGULAR VELOCITY RATIO.

NS        WS X T1

----    = ---- = ---------- = ----

N1        W1 (-TS/T1) X TS

   -T1            56

= ----   =    -------- = -4

    TS             14

HENCE, INTERNAL GEAR MAKES ONE REVOLUTION FOR 4 REVOLUTIONS OF SUN GEAR. THE NEGATIVE SIGN INDICATES THAT BOTH THE GEARS REVOLUTION IN REVERSE DIRECTION.

2.      CONDITION-2 (INTERNAL GEAR LOCKED)

IN THIS CONNECTION, LET US TAKE ONE REVOLUTION OF PLANET CARRIER.

Y=1 & Y -TS/T1 X=0

Y = TS/T1

PUTTING THE VALUE OF ‘Y’

TS/T1 X=1

X=T1/14 = 56/ =4

ALSO, PLANET CARRIER MAKES ‘Y’ REVOLUTIONS FOR (Y+X) REVOLUTIONS OF SUN GEAR.

HENCE, ANGULAR VELOCITY RATIO.

NS/NC= WS/WC= Y+X/Y

WHERE ‘NS’ AND ‘NC’ ARE THE SPEEDS OF SUN AND PLANET CARRIER RESPECTIVELY.

=4+1/1 =5

3.      TORQUE

LET, TS = INPUT TORQUE

TC = TORQUE ON PLANET CARRIER

T1 = TORQUE ON INTERNAL GEAR

IF FRICTION IS NEGLECTED.

INPUT POWER = OUTPUT POWER.

TSWS +TCWC + TIWI = 0

EITHER WC OR WI WILL BE ZERO

HENCE3, TS.WS = TC.WC (OR TI.WI)

4.  WITH THE CALIBRATION CHART OF MOTOR, FIND OUT TORQUE AT THE CURRENT READING

TS

TORQUE ON THE PLANET CARRIED

TC = [0.05+0.012/2]X 9.81XS.B.

DIFFERENCE

TORQUE ON INTERNAL GEAR

TI = [0.120+0.022/2]X9.81XS.B.

DIFFERENCE: TC = TS + TI

PRECAUTIONS:

·        DO NOT LOAD THE MOTOR ABOVE 1.9AMP. CURRENT.

·    BEFORE STARTING THE EXPERIMENT, PUT SOME LUBRICATING OIL TO GEARS & BEARINGS.

·        OPERATE ALL THE SWITCHES AND CONTROLS GENT.