ASE XEV2 flashcards
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32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Class 0 insulating glove rating
- Class 0 rubber insulating gloves are rated for maximum use at 1,000 V AC or 1,500 V DC and must be electrically retested every six months.
- Let-go current threshold
- About 10 to 16 mA of 60 Hz AC causes involuntary muscle contraction that prevents a person from releasing the energized conductor.
- Automotive high-voltage threshold
- ISO 6469 and SAE standards define high voltage as any circuit greater than 60 V DC or greater than 30 V AC RMS.
- CAT III meter rating
- A CAT III 1000 V meter is rated to withstand transients on distribution-level circuits and is the minimum for HV battery measurements.
- Arc flash incident energy
- Incident energy is the heat energy in calories per square centimeter at a stated working distance, and it sets the required arc rating of PPE.
- IEC 60900 insulated tools
- Hand tools marked to IEC 60900 are proof-tested at 10,000 V and rated for live work on circuits up to 1,000 V AC.
- Lithium-ion nominal cell voltage
- Most automotive lithium-ion cells have a nominal voltage near 3.6 to 3.7 V, a full-charge limit around 4.1 to 4.2 V, and a low limit near 2.5 to 3.0 V.
- Pack energy formula
- Pack energy in kilowatt-hours equals the amp-hour capacity multiplied by the nominal pack voltage, with the result divided by 1,000.
- Open-circuit voltage SOC limits
- Open-circuit voltage indicates state of charge reliably only after the pack rests, and resolution is poor through the flat middle of the discharge curve.
- Passive cell balancing
- Passive balancing discharges the highest-voltage cells through resistors, wasting the excess energy as heat but adding little cost and complexity.
- Insulation resistance pass rule
- ISO 6469-1 requires DC isolation of at least 100 ohms per volt of pack voltage, so a 400 V pack must measure 40,000 ohms or more.
- Thermal runaway warning signs
- Swelling, a sweet or solvent odor, hissing venting, and cell temperatures above roughly 60 degrees C indicate a battery approaching thermal runaway.
- Back-EMF while spinning
- A permanent-magnet motor generates voltage proportional to rotor speed, so its terminals stay hazardous after disablement whenever the wheels can turn.
- Motor mechanical power formula
- Mechanical power in watts equals torque in newton-meters multiplied by angular speed in radians per second; divide the result by 746 for horsepower.
- Field-oriented control axes
- Field-oriented control splits stator current into a d-axis component that sets flux and a q-axis component that produces torque.
- Regeneration limiting factors
- Regenerative braking torque is limited by battery state of charge, pack temperature, motor speed, and the thermal capacity of motor and inverter.
- Resolver purpose
- A resolver or encoder reports rotor position and speed to the inverter so current pulses can be synchronized to the rotor magnetic field.
- DC bus capacitor hazard
- Inverter bus capacitors can hold hundreds of joules after shutdown; bleed resistors discharge them, but the OEM wait time must still be observed.
- Silicon carbide advantages
- SiC MOSFETs switch faster with lower conduction and switching losses than IGBTs, giving higher inverter efficiency and smaller cooling systems.
- Dead time purpose
- Dead time is a brief delay between turning off one power switch and turning on its complementary pair, preventing destructive shoot-through current.
- DC-DC converter function
- The HV-to-12 V DC-DC converter replaces the alternator, stepping pack voltage down to charge the 12 V battery and run vehicle accessories.
- Desaturation overcurrent detection
- Desaturation detection monitors the voltage across a conducting IGBT; a rapid rise signals excessive current and the gate driver shuts the device off.
- Control pilot duty cycle
- On SAE J1772, the control pilot PWM duty cycle encodes the maximum current the EVSE can supply, at 0.6 amps per percent of duty.
- CC-CV charging profile
- The charger holds constant current until cells reach their voltage limit, then holds constant voltage while current tapers toward zero.
- AC Level 2 power
- Level 2 charging uses a 240 V AC supply through the on-board charger and typically delivers between 3.3 and 19.2 kW.
- On-board charger role
- The on-board charger rectifies AC input, corrects power factor, and regulates isolated DC output to the pack during AC charging.
- Proximity pilot resistor
- The proximity pilot circuit uses a resistor value built into the charge plug to tell the vehicle the current capacity of the connected cable.
- HV disablement wait time
- After the 12 V battery and service disconnect are removed, technicians wait the OEM-specified time, often 5 to 10 minutes, for capacitors to discharge.
- Three-point voltage verification
- Measure HV positive to HV negative, HV positive to chassis, and HV negative to chassis; every reading must be below the OEM limit, typically 30 V.
- Meter self-check requirement
- Confirm the voltmeter reads correctly on a known live source immediately before and immediately after each HV dead check.
- Manual service disconnect
- The manual service disconnect is a serviceable high-voltage connector, often containing a fuse, that physically opens the pack circuit for repair.
- Never break HV under load
- Opening a high-voltage connector while current is flowing sustains an arc that can melt terminals, ignite materials, and cause severe burns.