EVITP Medium/Heavy-Duty, Fleet and DC Fast Charging Installations

Question 1

What supply is most commonly used to feed commercial DC fast chargers in the United States?

Accepted Answer

480 V three-phase

Answer

Most U.S. commercial DC fast chargers take a 480 V three-phase supply, which delivers high power at manageable conductor sizes.

Question 2

Which SAE standard covers automated overhead (pantograph) conductive charging, as used for transit buses?

Accepted Answer

SAE J3105

Answer

SAE J3105 defines automated conductive charging through connection devices such as overhead pantographs, which are common at transit bus layover points.

Question 3

What is the Megawatt Charging System (MCS) mainly designed for?

Accepted Answer

Heavy-duty trucks and buses that need multi-megawatt charging

Answer

MCS, standardized as SAE J3271, is a high-power DC connector system for Class 8 trucks and other heavy-duty vehicles with very large battery packs. It supports power in the megawatt range.

Question 4

Why do many high-power DC fast chargers use liquid-cooled charging cables?

Accepted Answer

To carry very high current with a cable that stays light and flexible enough to handle

Answer

At several hundred amps, an air-cooled cable would need very large conductors and become too heavy for users to handle. Liquid cooling removes heat so the cable can stay smaller.

Question 5

A transit depot plans to charge 10 buses at the same time, each on a 150 kW charger. What is the peak charging demand?

Accepted Answer

1.5 MW

Answer

10 × 150 kW = 1,500 kW, or 1.5 MW. Loads this size often need utility coordination, a dedicated transformer and possibly managed charging.

(EVITP) Electric Vehicle Infrastructure Program Practice Test

(EVITP) Electric Vehicle Infrastructure Program Practice Test

EVITP Medium/Heavy-Duty, Fleet and DC Fast Charging Installations