what are short straps used on capacitors during maintenance
prevent them from recharging
what are the two parts of the long term LOTO log
Long Term index sheet
LOTO safety certificate
Precautions on dead electronic equipment
- isolate/carry out tag procedure
- prove that it is dead - GPTME
- Discharge any capacitors - GPTME
- if required, fir short straps, to stop recharge
What are the four major parts to the LOTO system
LOTO index sheet
LOTO label
LOTO Safety certificate
LOTO Display board
What is the procedure for LOTO
- obtain permission
- identify isolation points
- inform the users
- Fill out the LOTO index sheet in section 3 and collect serial number
- complete sections on LOTO safety certificate
- ensure equipment is off and isolated, then attach part A to the emptry fuse holder
- place part B on the relevent section on the LOTO board
- attach part C to the removed fuses and place them in the fuse box
What should happen to the labels after reinstalling a LOTO
Handed back to the authorising person and destroyed
What is a CP
- Capable person
- person who has sufficient technical knowledge
has experience in the subject - avoids danger from hazards
What is the resistance of the human body, when dry
1K ohms (1000 ohms)
What is HV safe
- informs personal that a compartment is safe to enter
- all forms of HV power sources are disconnected
- Appropriate HV decay periods have elapsed
- only used with the clearly identified compartment
What is HV Dead
- ship is no longer capable of generating, distributing or recieving HV
- All sources of HV supply are disconnected and isolated
- With circuit main earths applied
What is LOTO
Lock-Off/Tag Out
What is the purpose of LOTO
- provides a common method, for the isolation of mechanical/pneumatic, hydraulic and electrical systems/equipment
- minimum level
how would you prove that a circuit is dead before working on it
by measuring zero volts between phases and between phase and earth
What is HV live
- that HV can be generated
- informs peronel that HV is being generated
- That the ship is connected to an external HV shore supply
Reasons for isolating supplies using the LOTO system
- allows maintenance to proceed without hazard to equipment
- isolate equipment that is defective and its operation may be dangerous
- prevention of ‘mode selection’ of operation equipment, may be dangerous or unavaliable
- where equipment has been removed
what are the three hazardous components you encounter
- tantalum capacitors
- selenium rectifiers
- loxotane
list the three types of hand-over switchs
- Normal/Alternative change over
- Normal/Emergancy chane over
- Normal/Alternative/Emergancy change over
How do we tackle the accident problem
- know the hazard
- maintain safety discipline
- develop the habit of noticing potential dangers
What is GPTME
General Purpose Test Measuring Equipment
Precautions to be taken when working on live electronics
- Ask for authorisation
- dont take risks
- use insulated tools
- use rubber mats
- Never on volts about - 1000v AC / 1500v DC
- wear correct PPE
- All equipment is to be indate/tested
*Don’t work alone
*Know the voltage being worked on
*Don’t lean
*Don’t rely on safety equipment
What happens to the human body when exposed to
* 1ma
* 10ma
* 20ma
* 30ma
- 1ma - involuntary reaction
- 10ma - prevent you rom releasing
- 20ma - physical damage
- 30ma - can kill
What voltage on board is considered to be ‘safe’
24V DC
What are the major causes of accidents
- physical hazards
- pre-occupation
- ignorance or lack of skill
- over familiarty
- lazyness or fatigue
- horseplay
What is Ohm’s law
V = I x R
