Electric Construction Equipment 101: Terms and Definitions

If you’re new to electric construction equipment or just looking for a resource to brush up on terminology, this article is for you. It can help you better understand electromobility so you’ll have more meaningful conversations with others when talking about electric heavy equipment.

Common Electrical Construction Equipment Terms

Below are the most common terms you’ll hear as you talk more about electric heavy equipment.

• EV (Electric Vehicle): Any on-road or off-road vehicle that’s fully powered by electricity.
  • BEV (Battery Electric Vehicle): EV where the electrical energy is derived from battery sources.
  • Hybrid BEV: BEV with an electrical power source supplemental to the battery pack. For example, a diesel-electric hybrid will have a diesel internal combustion engine that charges the batteries, which in turn power the vehicle’s functions.
• Amp (A): A unit for measuring electrical current flow. Amps determine how much electricity is flowing.
• Volt (V): The unit of measurement of force used to produce an electric current. Volts indicate the electric force from the power source. An easy way to understand the difference between voltage and amperage is to compare it to flow and pressure on a hydraulic system — volt would be the pressure and amperage the flow. Voltage is a measure of the pressure that allows electrons to flow, and amperage is a measure of the volume of electrons.
• Watt (W): The base unit for measuring overall electric power. A watt of electrical energy is defined as the one amp times one volt.
• Kilowatt (kW): A unit for measuring electrical energy and equal to 1000 watts. For example, the demand for electricity of each of your home appliances is measured in kilowatts. A kilowatt of energy can be converted to 1.341 horsepower, the common unit of energy in internal combustion engines.
• Kilowatt Hour (kWh): A unit of energy equal to one kilowatt of power sustained for one hour. This measurement is used to determine the amount of power consumed over time and battery capacity.
• Grid: A power system’s interconnected network (generating plant, transmission lines, substations, etc.) that delivers electricity to consumers.
• AC (Alternating Current): An electric current that periodically reverses direction.
• Hertz (Hz): The rate (period) at which an alternating current reverses direction. Hertz is cycles per second — therefore a 60 Hz AC current changes direction 60 times per second.
• DC (Direct Current): An electric current flowing in one direction.
• Inverter: Devices that convert direct current (DC) electricity to alternating current (AC) electricity. Batteries deliver and charge from DC currents — the grid and common plugs are AC current.
  • AC Level 1 Charging: AC Level 1 chargers plug into a common household 120-volt AC outlet. It’s the slowest type of charging.
  • AC Level 2 Charging: AC Level 2 chargers plug into a 240-volt AC outlet. Charging on a 240V outlet is recommended as the charging time is reduced due to the higher power output.
  • DC Fast Charging: Quickest method for battery charging. DC current is supplied directly to the batteries at the corresponding voltage through a Remi plug (<100V) or a combination J1772 plug with DC pins (CCS1).
• Rectifier: Devices that convert alternating current (AC) to direct current (DC) electricity. Rectifiers perform the opposite function of an inverter.
• Convertor: Devices that change the voltage of a DC current. For example, Volvo compact electric machines use a convertor to step down the lithium-ion battery voltage from 48V to 14V to provide a slow charge for the lead-acid battery.
• SAE J1772 (J Plug): The North American standard for electrical connectors for electric vehicle AC charging, shown below.

• SOC (State of Charge): Approximate measure of energy remaining in a battery system. SOC is normally expressed as a percentage of maximum charge.
• Run Time: The time a machine can operate on a fully charged battery in a particular duty cycle.
• OBC (On-Board Charger): Component on an EV that converts AC J1772 input to the requisite DC current needed for charging using a rectifier.
• PDU (Power Distributor Unit): Device that manages the optimal electrical energy draw from the batteries needed to perform the required machine functions.
• Electric Machine Management Application: A Volvo web application providing real-time insight into a single or entire fleet of electric machines, including battery status, geographic location and more.
• Lithium-ion Battery: The rechargeable battery used in Volvo electric machines. Lithium-ion batteries use lithium ions to transfer electrical energy (electrons) between the Cathode (+) and Anode (-) sides of the batteries. These batteries have no memory effect, low self-discharge and can be quickly charged in comparison to lead-acid batteries.
• Lead-Acid Battery: Traditional automotive battery using one porous lead anode (-) and a lead dioxide cathode (+), immersed in a sulfuric acid electrolyte. Lead acid batteries are used in Volvo electric equipment to provide auxiliary electric energy for control systems, lights and auxiliary components. The lead-acid batteries on BEVs can be trickle-charged from the main lithium-ion battery using an onboard convertor.
• Renewable Charging: Charging an electric machine using non-fossil fuel generation (examples include solar, wind and hydroelectric).

Terms Related to Noise Levels

• Decibel (dB): A unit used to measure sound power levels using a logarithmic scale. Every 10 dB increase is an increase in the sound power by a factor of 10. For example, 0 dB (threshold of human hearing) to 10 dB has 10 times the sound power (10¹), 10 dB to 20 dB has 100 times the sound power (10²), and a 60 dB (10⁶) noise source is 1,000,000 times the sound power of a 0 dB source.
• Perceived Noise Level: The human ear reaction to sound levels works on logarithmic progression, just like the decibel scale. So, even though the sound power is increasing by factors of 10x, our perception is that a 10 dB change is twice as loud. For example, a 20 dB to 30 dB change is 1000 times the sound power, and we would perceive it as twice as loud. Similarly, an increase from 50 to 60 dB is an increase of 1,000,000 times the sound power, but we’ll still perceive it as twice as loud. On the ECR25 electric excavator, for example, exterior noise levels were reduced from 93 dB to 84 dB. This means the 9-decibel decrease makes the electric machines to be about half as loud as their diesel counterpart.

Outlets with Volvo Adapters for Charging Electric Equipment

The image below shows you the NEMA 5-15 and NEMA 14-50 electrical outlets which are recommended for AC charging BEVs. These are the two outlets Volvo makes adapters for to charge electric machines.

Environmental Terms

• Sustainability: Involving methods that do not completely use up or destroy natural resources.¹ At Volvo CE, we firmly believe that for a sustainability initiative to be meaningful, it must be environmentally and socially beneficial, as well as economically viable.
• Greenhouse Gases: Any of various gaseous compounds (such as carbon dioxide or methane) that absorb infrared radiation, trap heat in the atmosphere and may contribute to warming our planet’s surface and lower atmosphere.¹
• Low Emissions: Fuels and machines that have a low emissions level in comparison to fossil fuel combustion sources. Biofuels and additives (ethanol) are common low-emission fuels.
• Zero Emissions: Vehicles and machines that don’t produce (emit) any harmful gases during operation.

¹ Merriam-Webster

By Dr. Ray Gallant and Lars Arnold