What are the types of steering systems?
An electro-hydraulic steering gear system
Ram type system (2 or 4 ram) and Vane type system
An all-electric steering gear system
Ward Leonard system and Single motor system
What is hunting gear?
Hunting gear is acting as a feedback mechanism. Hunting gear transmits the position of the rudder to the p/p control lever by the floating lever
What are the safety devices for the steering system?
ELECTRICAL
- The motor should able to carry 200% of full load current
- 200% of motor insulation
- Overload alarm
- Phase failure alarm
- Power failure alarm
- Short circuit trip
- One motor should be connected to ESB
- Should start zero time delay after power failure recovered
MECHANICAL
- Hydraulic tank low-level alarm
- Hydraulic tank low-low level trip-safematic
- Hydraulic oil temperature high alarm
- Filter clogged alarm
- Hydraulic lock alarm
- Angle adjusting stopper (limit switch at PORT & STBD side)
- Relief valve
What is the indication of air in the steering system?
- Jerky movement
- Jumping pressure gauges on the system
- Defective steering operation
What is the effect of air within the steering system?
It is lead to incorrect balance between units, time lags and irregular operation
Steering gear maintenance
Before departure
- Checks carried out as per checklist
- Visual inspection
- Checking the function of the steering gear
- Check safety equipment and make sure the all alarms are functioning properly
- Actual rudder angle and indicator
- Communication system
Daily
- Visual inspection: deformations, cracks, missing mechanical connectors, defective mechanical or electrical connections
- Motor load current and temperature
- Check for unusual noises
- Visual inspection for leaks in the hydraulic system
- Check oil level on the oil expansion tank
- Greasing
Weekly
- Check oil level on the oil storage tank
- If steering gear equipped with safematic system: check that safematic is functioning properly
- Visual inspection of automatic grease lubricator and hoses
Every 3 months interval
- As per manufacturer information
- Thorough inspection: deformations, cracks, missing mechanical connectors, defective mechanical or electrical connections
- Limit switch operation
- Emergency steering gear drill.
- What is the purpose of buffer spring?
- Buffer spring used to protect the control system from the damages.
Ward Leonard system
This is an electrical type steering gear system. Ward Leonard system controls the speed of DC (direct current) motor from zero to maximum in either direction.
What is the hydraulic lock?
In this situation, the rudder is not responding to the command
What are the reasons for the hydraulic lock?
- The air into the system
- Hydraulic oil dirty renew hydraulic oil
- Synchro transmitter or receiver malfunctioning
- Sluggish movement of the rudder
- Very frequent movement
- Limit switch malfunctioning
- Main pump malfunction
- Rudder angle having the error
- Hydraulic lock alarm unit malfunctioning or defective
How to recover the system from the hydraulic lock?
- Take control to local
- Purging out the air If air in the system
- Check the Synchro system
- Check the limit switch operation
- Check the rudder movement for proper operation
How to try out hydraulic lock alarm?
- Take control to local
- Press both solenoid at the same time
- Both limit switches activate at the same time
The steering gear is not responding to the command what will be the reasons?
- Steering Angle Indicator faulty.
- Solenoid not working
- Oil level low
- The switch is in Manual
- PI Controller faulty
What is the significance of 200% insulation in steering gear motor?
It means that motor winding can withstand 200% of FLC
What are the FU and NFU mode?
FU - follow up
- FU has two modes
- Auto and manual
- Auto - autopilot command
- Manual - hand steering and once u give a command like 10-degree port then rudder go to 10-degree port then it comes to midship
NFU - no follow-up
- NFU mode in simple words emergency steering from the bridge
- All controls bypassed
- In this rudder will not come to Midship once u give the command
Critical spares for steering gear?
- Synchro transmitter and receiver
- PID controller
- Steering gear motor and its control ckt spares (contactors, breakers)
- Limit switches
- Proximity switches
- Rudder angle indicator etc.
Why is time delay in when starting a steering gear motor?
2-sec delay because servo pump start in prior to the main pump
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8 Comments
Nice work
ReplyDeleteThough most of you must be aware as an ETO / Marine Engineer --- the Steering Gear Motor Rotors are supported on the Motor End Covers on 3 Ball Bearings and not on 2 ball bearings as rest of the motors on board ship. Please answer about arrangement of these 3-ball bearings on the rotor. Why?
ReplyDeleteDr Mukesh Kumar
Ex-ETO
BSM
MUKESH63.K@GMAIL.COM
Thanks for your work. Very educative
ReplyDeleteAfter stoping rotory ven steering gear hyd pump at mid ship the steering slowly moved to 35deg max STBD. Could any one advice how to solve the problem?
ReplyDeleteWhy did sterring power is alarm when sterring gear pannel alarm is on?
ReplyDeletewhat are you talking about... Maybe relay, maybe no power to motor, maybe loose contacts, maybe this and that. Describe the issue properly to receive answer.
DeleteThere is no regulation of 200% insulation in steering gear regulation. It is only about passage of current shall not be less than twice of FLA including starting current. Kindly update it.
ReplyDeleteThnx buddy
ReplyDeleteWe love to hear your comments on this article, so that we may better serve you in the future.