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WorksheetsHigh Voltage Tester requirements for SiC products
Total questions: 20
Worksheet time: 10mins
How big the voltage is under High-Voltage testing?
DC voltage over 500V
DC voltage over 1000V
DC Voltage over 1500V
DC Voltage over 2000V
How big is the current that can kill human?
less then 1mA
less then 100mA
less then 1A
less then 5A
What is typical Human Body resistance?
50 Ohms
250 Ohms
500 Ohms
5000 Ohms
A company produces a SiC Mosfet and perform Breakdown voltage test at 2700 Volts. Can it kills human?
yes
No
Yes if the human is thin.
Yes if the human wear rubber shoes and very dry.
My 1200 V SiC Mosfet will evolve to 4700 Breakdown voltage in the next 3 years. What kind of voltage ratings that should i buy for my tester?
1500 V
3000 V
4500 V
5000 V
This fact is wrong.
Cable must be designed to able to withstand to the max ratings of the tester
Cable must be very short
Cable must be designed to be able to dissipate heat
Must have a thermometer in the fixture
Raju designed two grounding paths with the same resistance value. He measured total cum contact resistance on the source to ground is 0.2 ohms. Raju run a HV testing that generates 100A of current, How much power is dissipated for each of the ground pin?
500 Watt
1000 Watt
1500 Watt
2000Watt
Why HV test fixture must be properly grounded?
to reduce the temperature at HV testing
To ensure no sparking if overvoltage occured
To ensure any leaking current to be absorbed by earth for safety to the operators
to extend the reliability of the test fixture as they are normally very expensive
Below are the reasons why we need to run HV testing as fast as possible except ...
to minimize further loss due to power dissipation at the contacts resistance
to minimize damage on fixture, device and other components if there is issue on contacts, wear and tear or human error.
to reduce overheating in certain components for eg power cable
It can cause power trip for the entire plant if run for too many testers
What is Kelvin connection?
is a connection that has sensor to measure the temperature
it has a mechanism to convert oC to K. 1K = -273.15 oC
it uses special material to reduce the overheating during HV testing
It uses 4 terminal sensing to make more accurate measurements then the conventional 2 terminal type
Which one is not true? based on the picture.
The SOP must force operator to wear good quality of rubber shoes for safety purposes in HV testing
Without good insulation on the operator, the High Voltage can cause severe injury and probability dealth to the operator
Good grounding on the floor will save lives if electrical shock occured
Food and drinks are not allowed in HV testing, because water is conductor and can promote grounding to the operators
Why we need a counter at the HV test fixture?
because the PM cud be scheduled accurately
Counter will help to count how many units that passed the testing
The counter will determine the life-span of the test fixtures.
The counter will help in the UPH computation
Below are the reasons why Batch ID for operators need to be scanned during HV testing except ....
to store operators name in the DB
The tester will automatically unlock for authorized operators
for future references such as if there is an error found or any problems encountered due to human errors
to unlock priveleges at all testers features based on user hierachy
Rubber glove can protect from 12,000 V electric shock. Which one is false .....
No, this statement is a myth.
Yes provided the glove is thick enough for HV use
Yes provided the gloves is 100% made from rubber
Yes provided the gloves do not have any tear
Select item which is not true about safety enclosure box in HV testing?
It must be designed from good insulation materials to protect operators from electrical shock
It must have temperature sensors
The cable and materials must be design based on the max ratings of the testers
Using with a safey interlock features at tester is an added advantages
What is the best grounding resistance for equipments in plant?
less then 100 Ohm
less then 50 Ohm
Less then 25 Ohm
Less then 5 Ohm
How ground fault circuit interruptor works?
It compares current go and back from equipment
It compares total current used by the loads
It compared total Voltage used by the loads.
It will trip if the current is more then trigger limit
What is the safe distance from overhead lines?
20 feet
15 feet
10 feet
5 feet
All of these statements are correct except ...
Extension cords should not be used in office area
extension cords should only be limited to maintenance personnel.
employee should know the location of ELCB for their equipments
Employee can plug out and plug in the power cord cable without looking at it.
These are required in HV testing bay except ....
HV gloves for the operator
ESD suit
Face protection apparatus
linen thin smock shoes
