Motorised valve actuator
1. What are the advantages of motorised valve actuators?
Advantages
a. Can be used to operate in remote areas, high heat areas etc.
b. Suitable logics can be wired up easily.
c. Hammer blow mechanism (which will release valve in stuck open or close). The
motor has high torque.
2. What are the four basic parts of any valve actuators?
a. Valve motor.
b. Gear mechanism.
c. Limit switch and torque switch assembly.
d. Terminal box.
3. Explain how the motor motion is transmitted to the valve stem?
The motor shaft is connected to a spar gear. It engages on a worm wheel. The worm
wheel has dog teeth. This dog teeth engages or hits the dig teeth on moving or sliding
clutch. The sliding clutch has splines and these are on the splines of valve stem. So
when the sliding clutch rotates the valve also rotates simultaneously.
4. Do you require separate limit switch for closing and separate limit switch for
opening? Ans. YES.
5. What does the limit switch mechanism senses to operate?
Limit switch mechanism senses whether the open and close travel of the motor has
exceeded the limit setting of the motor to operate.
6. What does the torque switch mechanism senses to operate?
Torque switch senses whether the torque of motor has exceeded the set point
irrespective of position of valve.
7. Explain the operational aspects of limit switch and torque switch in rotork valve
actuator.
a. When limit function is selected?
b. When torque function is selected?
Limit function – when limit function is selected in rotork valve, the limit switches
will operate when the limit set points are reached. Suppose limit switches fails to
operate the torque switches will act and cuts off the supply to the motor (both torque
switch and limit switches can act when selected to limit function).
Torque function – when torque function is selected the torque switches will act when
set point is reached. The limit switches will not act (only torque switch will act when
selected to torque function).
8. Indicate how you will select the limit switch contacts for indication and for cutting
the supply to the motor?
For cutting off the supply to the motor normally closed (NC) contacts of limit switch
(LS) should be wired in series with interposing relay coil of respective direction of
the valve so that when valve reaches their respective direction contact will open and
cut the control supply. For indication normally open contacts (NO) of opposite
direction of valve should be used so that when valve fully closes open indication
contact should remain NC only and vice-versa.
So for close direction
NC contact of close direction
9. What indication will you get in control room when
a) valve is open – green
b) valve is closed – amber
c) valve is intermediate – both
d) valve is closing and torque switch operate – both
10. What is the function of hammer blow mechanism?
Hammer blow mechanism allows motor to rotate freely for ½ or ¼ turn and the dog
teeth on worm gear comes against the dog teeth on sliding clutch with a blow. This is
use full when valve is stuck in fully open or closed condition.
11. How will you proceed to operate the valve manually after an electrical operation?
After electrical operation to operate manually we must tilt the lever provided on the
actuator to hand (manual) position by which the sliding clutch gets engaged with
hand drive.
https://www.youtube.com/channel/UC4_D50vMu1wbQrPaLFYo6Eg https://www.youtube.com/channel/UC4_D50vMu1wbQrPaLFYo6Eg RRB JE, SSC AE/JE UPSSSC JE, SSC JE, CIVIL ENGINEERING MCQs, ELECTICAL ENGINEERING MCQs, preavious year quesion papers, dmrc, lmrc, drdo,rrb ntpc, ntpc, pgcil, dsssb, states board, GATE IES EE, ESE, ECE, ME, CE, IT & CS EXAM MATERIALS & OLD PAPERS Electrical Engineering https://t.me/pravendrarajpoot Daily news & current affairs in hindi & english fully updated Daily current affairs https://t.me/newsdailypkr Engineering Discussion group for your upcoming exams, you can ask your any query regarding your problem,๐๐๐ https://t.me/joinchat/JObxeA7n6S4qvnegrGhTgA PKR ELECTRICAL ENGINEERING I am sure this is the best place for you guys subscribe and get success IF YOU WANT TO JOIN ME ON TELEGRAM FOR PDF @newsdailypkr AE/JE EE, ESE, ECE, ME, CE, IT & CS EXAM MATERIALS & OLD PAPERS Electrical Engineering https://t.me/pravendrarajpoot facebook page:- Pravendra Kumar Rajpoot https://t.me/newsdailypkr https://chat.whatsapp.com/5AS7dNFTP4H4vVsiWsqHrT https://t.me/srk50 https://t.me/pravendrarajpoot https://t.me/joinchat/JObxeA7n6S4qvnegrGhTgA https://t.me/pravendrarajpoot Daily news & current affairs in hindi & english fully updated Daily current affairs https://t.me/newsdailypkr Engineering Discussion group for your upcoming exams, you can ask your any query regarding your problem,๐๐๐ https://t.me/joinchat/JObxeA7n6S4qvnegrGhTgA PKR ELECTRICAL ENGINEERING I am sure this is the best place for you guys subscribe and get success IF YOU WANT TO JOIN ME ON TELEGRAM FOR PDF @newsdailypkr AE/JE EE, ESE, ECE, ME, CE, IT & CS EXAM MATERIALS & OLD PAPERS Electrical Engineering https://t.me/pravendrarajpoot facebook page:- Pravendra Kumar Rajpoot https://t.me/newsdailypkr https://chat.whatsapp.com/5AS7dNFTP4H4vVsiWsqHrT https://t.me/srk50 https://t.me/pravendrarajpoot https://t.me/joinchat/JObxeA7n6S4qvnegrGhTgA
1. What are the advantages of motorised valve actuators?
Advantages
a. Can be used to operate in remote areas, high heat areas etc.
b. Suitable logics can be wired up easily.
c. Hammer blow mechanism (which will release valve in stuck open or close). The
motor has high torque.
2. What are the four basic parts of any valve actuators?
a. Valve motor.
b. Gear mechanism.
c. Limit switch and torque switch assembly.
d. Terminal box.
3. Explain how the motor motion is transmitted to the valve stem?
The motor shaft is connected to a spar gear. It engages on a worm wheel. The worm
wheel has dog teeth. This dog teeth engages or hits the dig teeth on moving or sliding
clutch. The sliding clutch has splines and these are on the splines of valve stem. So
when the sliding clutch rotates the valve also rotates simultaneously.
4. Do you require separate limit switch for closing and separate limit switch for
opening? Ans. YES.
5. What does the limit switch mechanism senses to operate?
Limit switch mechanism senses whether the open and close travel of the motor has
exceeded the limit setting of the motor to operate.
6. What does the torque switch mechanism senses to operate?
Torque switch senses whether the torque of motor has exceeded the set point
irrespective of position of valve.
7. Explain the operational aspects of limit switch and torque switch in rotork valve
actuator.
a. When limit function is selected?
b. When torque function is selected?
Limit function – when limit function is selected in rotork valve, the limit switches
will operate when the limit set points are reached. Suppose limit switches fails to
operate the torque switches will act and cuts off the supply to the motor (both torque
switch and limit switches can act when selected to limit function).
Torque function – when torque function is selected the torque switches will act when
set point is reached. The limit switches will not act (only torque switch will act when
selected to torque function).
8. Indicate how you will select the limit switch contacts for indication and for cutting
the supply to the motor?
For cutting off the supply to the motor normally closed (NC) contacts of limit switch
(LS) should be wired in series with interposing relay coil of respective direction of
the valve so that when valve reaches their respective direction contact will open and
cut the control supply. For indication normally open contacts (NO) of opposite
direction of valve should be used so that when valve fully closes open indication
contact should remain NC only and vice-versa.
So for close direction
NC contact of close direction
9. What indication will you get in control room when
a) valve is open – green
b) valve is closed – amber
c) valve is intermediate – both
d) valve is closing and torque switch operate – both
10. What is the function of hammer blow mechanism?
Hammer blow mechanism allows motor to rotate freely for ½ or ¼ turn and the dog
teeth on worm gear comes against the dog teeth on sliding clutch with a blow. This is
use full when valve is stuck in fully open or closed condition.
11. How will you proceed to operate the valve manually after an electrical operation?
After electrical operation to operate manually we must tilt the lever provided on the
actuator to hand (manual) position by which the sliding clutch gets engaged with
hand drive.
https://www.youtube.com/channel/UC4_D50vMu1wbQrPaLFYo6Eg https://www.youtube.com/channel/UC4_D50vMu1wbQrPaLFYo6Eg RRB JE, SSC AE/JE UPSSSC JE, SSC JE, CIVIL ENGINEERING MCQs, ELECTICAL ENGINEERING MCQs, preavious year quesion papers, dmrc, lmrc, drdo,rrb ntpc, ntpc, pgcil, dsssb, states board, GATE IES EE, ESE, ECE, ME, CE, IT & CS EXAM MATERIALS & OLD PAPERS Electrical Engineering https://t.me/pravendrarajpoot Daily news & current affairs in hindi & english fully updated Daily current affairs https://t.me/newsdailypkr Engineering Discussion group for your upcoming exams, you can ask your any query regarding your problem,๐๐๐ https://t.me/joinchat/JObxeA7n6S4qvnegrGhTgA PKR ELECTRICAL ENGINEERING I am sure this is the best place for you guys subscribe and get success IF YOU WANT TO JOIN ME ON TELEGRAM FOR PDF @newsdailypkr AE/JE EE, ESE, ECE, ME, CE, IT & CS EXAM MATERIALS & OLD PAPERS Electrical Engineering https://t.me/pravendrarajpoot facebook page:- Pravendra Kumar Rajpoot https://t.me/newsdailypkr https://chat.whatsapp.com/5AS7dNFTP4H4vVsiWsqHrT https://t.me/srk50 https://t.me/pravendrarajpoot https://t.me/joinchat/JObxeA7n6S4qvnegrGhTgA https://t.me/pravendrarajpoot Daily news & current affairs in hindi & english fully updated Daily current affairs https://t.me/newsdailypkr Engineering Discussion group for your upcoming exams, you can ask your any query regarding your problem,๐๐๐ https://t.me/joinchat/JObxeA7n6S4qvnegrGhTgA PKR ELECTRICAL ENGINEERING I am sure this is the best place for you guys subscribe and get success IF YOU WANT TO JOIN ME ON TELEGRAM FOR PDF @newsdailypkr AE/JE EE, ESE, ECE, ME, CE, IT & CS EXAM MATERIALS & OLD PAPERS Electrical Engineering https://t.me/pravendrarajpoot facebook page:- Pravendra Kumar Rajpoot https://t.me/newsdailypkr https://chat.whatsapp.com/5AS7dNFTP4H4vVsiWsqHrT https://t.me/srk50 https://t.me/pravendrarajpoot https://t.me/joinchat/JObxeA7n6S4qvnegrGhTgA
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