A
Ambient Temperature and Time Rating The rating of the motor is the ambient (room) temperature vs. the time it can operate at that temperature. Most motors are rated for continuous duty. The most common maximum ambient temperature rating is 40°C.
Ampere (Amp) The measure of electrical current. Amp ratings indicate the average motor input current the motor can be expected to draw under full load conditions. There are three common motor amp ratings:
- No-load amps is the current draw when the motor is unloaded.
- Full-load amps is the current required during full-rated load operation.
- Locked-rotor or start-up amps is the current when the motor rotor is stopped or locked and indicates the maximum amount of current that could be expected during the first few seconds of startup.
Annual motor expense (Change) = [Annual Motor Expense (Last Year) – Annual Motor Expense (YTD)] / Annual Motor Expense (Last Year). Expressed as %; indicator denotes trend.
Annual motor expense (Last Year) Compares year-to-date time Motor Energy Expenses to the comparable period from the previous year.
Annual motor expense (YTD) Year-to-date cumulative Motor Energy Expense.
Apparent power (kVA) = √3 × Voltage (V) × Current (A).
B
Baseload Continuous minimum flow conditions required in the pump optimization scenario; e.g., non-weather related demand.
Base year The year used as a baseline to assess on-going energy performance.
Bearings DE Drive-End bearing model; i.e., primary shaft end.
Bearings ODE Bearing model for the Opposite-Drive-End; i.e., the fan end, rear, or secondary shaft end of the motor.
Breakdown torque The maximum torque that an operating motor can produce before stalling.
Best practice motor efficiency This value is the highest efficiency motor available on the market of equivalent size and specification to the motor being analyzed.
Best practice pump hydraulic efficiency This value is the highest pump hydraulic efficiency calculated via measurements on this pump.
C
Catalog motor efficiency = 100 – [(Equivalent Catalog Motor Efficiency – Motor Actual Efficiency) ÷ Equivalent Catalog Motor Efficiency]
Catalog number Manufacturer’s model identifier in their catalog; may or may not be different from model number.
CO2-e emission factor Different electric utilities source their electricity from varying generation technologies with higher or lower carbon emissions, thus each utility’s CO2-equivalent emissions factor denotes the average rate of greenhouse gas emissions caused by each kilowatt-hour of electricity sold.
Current (I; Amps) Current, measured in Amps, is the rate at which electric charge flows past a point in a circuit.
D
Design Friction Losses The estimated (calculated) friction losses in a piping system, in meters of head per kilometer of pipeline, if known. If unknown, Motors@Work uses length of discharge pipe and system pressure to calculate friction losses.
Demand (kW) Demand is the instantaneous use of energy. Utilities typically measure demand as the highest rate of energy use in a 15- or 30-minute (0.25- or 0.50-hour) period, making the units actually kilowatt-hours per hour, often shortened to simply kilowatts.
Demand Charges The component of electric utility bill that’s proportionate to peak demand for billing period. Demand charges are common for industrial and commercial customers in the United States.
Design There are seven standard motor designs: DC refers to all direct current motors. Synchronous refers to all permanent magnet, synchronous-speed motors. Induction motors are divided into IEC and NEMA designs. IEC, also known as metric, motors follow international standards for frame sizing. NEMA, which uses imperial units, designates five classes of induction motors based on torque-speed performance characteristics; for more on the characteristics of NEMA motors, see NEMA Design.
Drive system The gear box, belt system, pump, fan, compressor, or other equipment driven by the motor.
E
EAM system An enterprise asset management (EAM) system manages an organization’s physical assets, including the design, construction, commissioning, operations, maintenance and decommissioning or replacement of plant, equipment and facilities. EAM systems typically manage assets enterprise-wide, across department, location, facility, and business units.
Full-load efficiency The percentage of input electrical power that the motor converts to work output from its shaft(s). While there are several methods of measuring motor efficiency, Motors@Work reports nominal full-load efficiency as measured according to IEEE Test Standard 112-B, which uses a dynamometer to test motor output at specific load levels.
Electricity consumed (kWh) Also known as energy, electricity consumed denotes the quantity of energy (kWh) your utility provider charges you for using in a given billing period.
Electricity cost ($) Electricity cost is the total amount, in dollars, that your utility provider charges you for the energy used in that billing period.
Enclosure The style of the housing and cooling method a motor uses. Different motor enclosures withstand various levels of exposure to moisture, particles, and chemicals. The four most common types of enclosures are Open Drip Proof, Totally Enclosed Fan Cooled, Totally Enclosed Non-ventilated, and Explosion Proof; less common enclosures include Weather Protected, Hazardous Location, Totally Enclosed Wash Down, and Totally Enclosed Air Over.
Energy (kWh) Energy, typically measured in units of kilowatt-hours (kWh), is the summation of power (or demand) over a defined time increment. Nearly all electric utility bills are based, in part, on the quantity of energy used.
Energy-efficient motor A motor with a nominal full-load efficiency that meets or exceeds the efficiencies in NEMA MG-1 Standard, Table 12-11, is considered an energy-efficient motor per the Energy Policy Act of 1992 (U.S.). Many manufacturers sell motors with efficiencies significantly higher than this standard, designated as NEMA Premium™ motors. NEMA Premium™ motors must achieve the efficiency values in Table 12-12 of the NEMA MG 1 Standard. Per the Energy Independence & Security Act of 2007, all integral horsepower motors less than 500 Hp sold in the U.S. must meet at least NEMA Premium™ efficiency levels. Motors that exceed NEMA Premium™ levels are classified as “Super Premium” efficiency.
ENERGY STAR™ rating EPA’s ENERGY STAR Portfolio Manager helps manage the energy performance of properties you own, manage, or hold for investment. Thousands of commercial and industrial organizations have used Portfolio Manager to benchmark the energy performance of their facilities operations, to assess improvements, and to apply for recognition from EPA. Top-performing buildings can earn an ENERGY STAR rating once they show a 10%, 20%, 30% (or more) reduction in normalized energy use. Those that achieve a 75 rating average or better earn the “ENERGY STAR Leader” recognition.
Energy performance indicator (EnPI; kWh per unit) The energy performance indicator, in units of kilowatt-hours per unit of production, allows plant operators to compare their performance both internally (i.e., internal benchmarking over a period of time) and externally (i.e., to other plants). Caution should be exercised when comparing EnPI across facilities as it is plant specific and influenced by variables such as plant size, total static head, motor efficiencies, etc.
Explosion Proof (EXPL) This motor enclosure is a variation of the Totally Enclosed Fan Cooled enclosure that’s specifically designed to prevent sparks or explosions caused by the motor from igniting flammable materials outside.
F
Fluid density The density of the fluid being pumped, typically in kilograms per cubic meter (kg/m³) or pounds per cubic foot (lbs/ft³).
Frame size NEMA and IEC define standard motor frame dimensions, denoted by the “frame” size. Frame sizes are typically a three- or four-digit number, and may include letters before or after the number for special shaft or mounting options (e.g., 405TS [short shaft]). Motors with the same frame designation have the same mounting pattern and shaft dimensions, ensuring consistency between different manufacturers.
Friction Loss (%) = 1 – Piping Efficiency (%)
Full-load speed (RPM) The speed that a motor turns when producing 100% of its rated load. For induction motors, full-load speed is typically two percent slower than their synchronous, or no-load, speed. Since even a small change in operating speed can affect the efficiency of pumps and fans, select a replacement motor with a similar full-load speed for these applications.
Full-load torque The torque a motor produces at 100% of its rated load.
G
Growing degree days (GDD) A simplified form of historical weather data, growing degree days is proportionate the amount of water needed for agricultural and landscaping purposes, and therefore useful to projecting the demand for water production.
H
Hazardous Location (HAZ) Hazardous-location motor applications are classified by the type of hazardous environment present, the characteristics of the material creating the hazard, the probability of exposure to the environment, and the maximum temperature level that is considered safe for the substance creating the hazard.
Hertz (Hz) The frequency, or cycles per second, that alternating current (ac) power changes directions, or the line frequency that a motor expects. In the U.S., line frequency is 60 Hz; many other countries provide power at 50 Hz.
Horsepower (Hp) A measurement of work done per unit of time, horsepower is the imperial unit for rating motors.
I
Insulation class Motor winding insulation is rated according to its thermal capabilities. Common designations are A, B, F, and H; the higher the letter, the greater the a motor’s tolerance for heat (both ambient temperature and motor temperature rise).
Intensity ($ per unit) The cost of energy used for each unit your organization produces.
Interval data Near real-time energy consumption related to a specific asset or meter (e.g. 5 min., 15 min., hourly, daily, weekly, or monthly).
Internal rate of return (IRR) A metric used in budgeting to assess the potential profitability of an investment, IRR is the discount rate one would need to apply to make the Net Present Value (NPV) of all projected cash-flows equal to zero.
K
Kilowatt (kW) The unit for instantaneous power draw, or electrical demand.
Kilowatt-hour (kWh) The unit for energy consumed over a period of time.
L
lb-CO2e emitted = Electricity Consumed (kWh) × Emission Factor (lb-CO2e/kWh)
Length of discharge pipe (m, km, ft) The length of discharge pipe used in the pumping system, often designated on system drawings.
Load factor (utility bill) The ratio between average demand and peak demand in a billing period. Load factor is a useful metric for determining whether to focus energy improvements on reducing energy consumption or shifting time-of-use demand.
Load factor (motor application) Occasionally found on packaged motor-fan and -pump units, load factor is the ratio between the motor’s output to drive the attached load to its rated (design) output. For example, a 10-horsepower motor driving a 7.5-horsepower load has a 75% load factor.
Locked-rotor current (Amps) When ac motors are started with full voltage (across-the-line), they draw 300% to 600% of their full-load current until they reach speed. The exact magnitude of this “in-rush current” is determined by motor horsepower and design characteristics.
M
Manufacturer The name of the company that manufactured the motor.
Meter The unique number assigned to every electricity connection and meter. The meter number enables geo-located tracking of each connection on the electricity network, no matter who the electric utility is. The meter number is prominently displayed on the electricity bills from your utility provider.
Model The model name or number designated by the manufacturer.
Motor energy expense The sum of the energy expenses associated with all motors tracked in Motors@Work in a specific month.
Motor loss (%) = 1 – Motor Efficiency (%)
Motor portfolio efficiency (%) = 100 – [(Nameplate Efficiency – Motor Actual Efficiency) ÷ Nameplate Efficiency].
Motor shaft power (kW) The mechanical power available at the output shaft of the motor; it is equal to the electrical power consumed minus motor losses, i.e., Motor Shaft Power (kW) = Electrical Power Consumed (kW) × Motor Efficiency (%).
N
National Electrical Manufacturers Association (NEMA) The trade organization of motor manufacturers, NEMA sets standards and publishes information used extensively in the motor industry.
NEMA Design NEMA establishes five induction motor designs, each with unique speed-torque-slip relationships, making them well-suited for different type of applications:
- Design A motors have a maximum of 5% slip, high starting current, and moderate locked-rotor and breakdown torque performance making them well-suited to a broad variety of applications
- Design B motors have a maximum of 5% slip, low starting current, and moderate locked-rotor and breakdown torque performance making them well-suite to general purpose and most fan and pump applications
- Design C motors have a maximum of 5% slip, low starting current, and high locked-rotor and breakdown torque performance making them well-suite to high inertial loads and applications where starting under load is required
- Design D motors have 5-13% slip at full-load conditions, low starting current, and high locked-rotor and breakdown torque performance making them well-suited to applications with high peak loads, such as rock crushers, oil-well pumping, winches, and hoists.
- Design E motors have a maximum of 3% slip, high starting current, and low locked-rotor and breakdown torque performance making them well-suited to centrifugal loads with low-starting torque requirements.
Nominal efficiency (%) The average efficiency of a operating motor at its rated (full) load, as determined by testing a sample of motors by the same manufacturer and model to IEEE Test Standard 112-B. Due to small variations in the manufacturing process, some motors may test a little higher or lower than their nominal efficiency at their rated load; NEMA established guaranteed minimum efficiency values to account for this variation. Motors@Work’s database uses nominal, rather than guaranteed minimum, efficiencies.
Net present value (NPV) The value of a stream of future cash-flows in today’s dollars, taking into account the time-value of money.
O
On-peak vs. off-peak A designation in time-of-use rates that indicates whether a that particular time of day, day of the week, and month of the year have high demand on the electric grid. Utilities typically charge higher on-peak rates than off-peak rates.
Open Drip Proof (ODP) A motor enclosure that allows ambient / external air to blow directly through the motor while preventing drops of liquid from entering. ODP motors are only suitable for protected environments.
P
Peak demand (kW) The highest rate of power drawn in a billing period. Utilities typically measure demand as the highest rate of energy use in a 15- or 30-minute (0.25- or 0.50-hour) period, making the units actually kilowatt-hours per hour, often shortened to simply kilowatts.
Phase (φ) The type of power supply a motor requires; ac motors are typically single-phase or three-phase. Three-phase electric power systems have at least three conductors carrying voltage.
Piping Efficiency (%) The efficiency of a pipework system, influenced by pipe roughness, straightness, and leakage. In Motors@Work, piping efficiency considers only discharge side piping; i.e., Piping Efficiency (%) = (Pump Discharge Pressure – Static Discharge Head) / Pump Discharge Head.
Power factor (PF) The ratio of the real power to apparent power, power factor is a measure of how effectively electrical power is being used. Induction loads, such as electric motors, reduce power factors. Most three-phase motors have a power factor rating to indicate how much reactive power they impose on the system. Significantly low power factors can reduce the efficiency of an entire electrical system, so many utilities industrial facilities with low power factor an added fee that is proportionate to either their power factor or reactive power (kVAR). Capacitors can be used to correct low power factor.
Power quality The level of voltage, phase balance, power factor, and harmonics in the power supply compared to ideal conditions. Poor power quality reduces the efficiency and reliability of electrical equipment, including motors. Various strategies, such as transformer adjustments and modifications to circuit loads, can be used to optimize voltage levels, correct phase balance, raise power factor, and minimize harmonics in the electrical distribution system, improving power quality.
Pump discharge pressure (m, ft of head; psi; bar) The pressure of pump discharge, typically measured within three diameters of the discharge flange of the pump using a pressure gage.
Pump discharge flow rate [m³/h, gpm (US), mgd (US)] The flow at the pump discharge as measured using a flow meter.
Pump hydraulic power output (kW) The power imparted to the fluid by the pump; it is calculated using the following formula: Pump Hydraulic Power Output (kW) = (Fluid Density (kg/m³) × Acceleration due to Gravity, g (m/s²) × Total Head (m) × Flow Rate (m³/h)) / 367,000.
Pump hydraulic efficiency (%) The efficiency by which a pump turns the input shaft power from the motor into useful hydraulic power, it is calculated using the following formula: Pump Hydraulic Efficiency (%) = Pump Hydraulic Power Output (kW) × 100 / Pump Input Shaft Power (kW), where Pump Input Shaft Power = Motor Shaft Power.
Pump Inlet, Outlet Diameter and Velocity Head : If the Pump Inlet Diameter is not equal to the Pump Outlet Diameter the difference in velocity head across the pump has to be accounted for (this figure will generally be very small). If the Inlet and Outlet diameters are equal the Velocity Head difference will be zero.
Pumping Loss (%) = 1 – Pump Hydraulic Efficiency (%)
R
Rate How electric utilities charge for service; for more, see Utility Rate.
RPM The speed at which a motor delivers torque at a given voltage and frequency. The difference between an induction motor’s full-load speed and its synchronous (no-load) speed is called slip. The amount of allowable slip is determined by the motor’s design. For most induction motors, its full-load speed is between 96% and 99% of its no-load speed.
Return on assets (ROA) An indicator of how profitable an organization is relative to the value of its capital assets, ROA indicates how efficiently management uses its assets to generate revenue.
Return on investment (ROI) The gain (or loss) generated on an investment relative to the time value of money and the quantity invested, ROI is typically used to compare the efficiency of different investment options.
S
Service factor A multiplier that indicates a motor’s ability to produce more than its designated full load. A 10-horsepower motor with a 1.15 service factor could run continuously provide (10 × 1.15) 11.5-horsepower without overheating. A motor with a 1.0 service factor cannot be expected to handle more than its nameplate horsepower on a continuous basis. Operating a motor above rated load reduces its efficiency and service life.
SIC Industry A number that indicates an organization’s primary business; for more, see Standard Industrial Classification (SIC).
Simple payback period (years) The time required for the energy savings from an investment to repay its initial costs with no interest or cost of capital considered.
Slip (%) The difference between an induction motor’s no-load (synchronous) and full-load speeds, expressed as a percentage of synchronous speed.
Speed (RPM) In Motors@Work, the field on the Measurements screen for entering the present operating speed of the motor. Motors@Work also records a motor’s synchronous speed and full-load speeds as part of its nameplate details; for the differences between these values, see entries for Full-load speed (RPM), Slip (%), and Synchronous speed (RPM).
Standard Industrial Classification (SIC) A four-digit code for classifying the primary business of companies by industry. In the United States, the six-digit North American Industry Classification System (NAICS code), released in 1997, generally replaced SIC codes; however certain government departments and agencies, such as the U.S. Securities and Exchange Commission (SEC), still use the SIC codes.
Starting torque (N-m, ft-lb) The maximum torque that the motor can produce from a complete stop or locked rotor.
Static suction head (m, ft) The vertical distance between the centerline of the pump inlet and the waterline of the source. If the source is above the pump, static suction head is negative; if below, static suction head is positive.
Static discharge head (m, ft) The vertical distance between the centerline of the pump discharge outlet and the waterline of the reservoir. If the reservoir is above the pump, the value is positive; if below, the value is negative.
Synchronous speed (RPM) The speed at which the motor’s magnetic field rotates. Synchronous and direct-current motors operate at synchronous speed under load; however, induction motors “slip” under load, operating at full-load speed at their rated load.
System efficiency (%) The overall efficiency of a pumping system, calculated as Motor Efficiency (%) × Pump Hydraulic Efficiency (%) × Piping Efficiency (%).
System friction losses (m, ft of head) Piping system losses on the discharge side of the pump, calculated as the difference between pump discharge pressure and static discharge head.
T
Thrust (N, lb-force) Thrust is a measure of the downward force a motor exerts on the bearings of a vertical-shaft motor.
Torque (N-m, ft-lb) A measure of torsional or twisting force measured in Newton-meters or foot-pounds. Three torque ratings are included in the Motors@Work Catalog.
Torque-speed Design (DES) Often abbreviated DES, this nameplate code and letter designation indicates the shape of the torque curve.
Total Harmonic Distortion (THD) While the grid ideally supplies perfectly sinusoidal ac voltage and current, in reality harmonics distort the waveform of the power most customers receive. Certain harmonics — multiples of the fundamental grid frequencies (50 or 60 Hz) — can be particularly damaging. These harmonics cause overloaded circuits, higher system losses, and premature equipment failure. Total harmonic distortion is a measure of how distorted these current and voltage waveforms are. Harmonics are also generally associated with low utility power factor.
Total Head (m or ft) Also known as total dynamic head, this value is the overall head supplied by the pump, including suction, velocity, and discharge heads.
Total installed Hp Total installed horsepower in the organization’s motor portfolio as managed in Motors@Work.
Total losses (%) = Motor Loss (%) + Pumping Loss (%) + Friction Loss (%)
Totally Enclosed Air-Over (TEAO) This dust-tight enclosure is designed specifically for shaft-mounted and belt-driven fans. The motor lacks internal cooling and must be mounted in the fan’s or blower’s air-flow.
Totally Enclosed Fan-Cooled (TEFC) Perhaps the most common induction motor enclosure, TEFC motors have totally enclosed windings. Fins and a fan provide cooling. TEFC motors function well outdoors and in dusty or contaminated environments.
Totally Enclosed Non-Ventilated (TENV) Motors with a TENV enclosure are not equipped for self-cooling, relying on external cooling (e.g., water-cooled jacket).
Totally Enclosed Washed Down (TEWD) Motor enclosures designed to withstand high pressure wash-downs or other high humidity or wet environments.
U
Utility budget (base year) Basis to monitor energy consumption and cost against base yea. Can be used to inform users of budget performance issues on a month-to-date and year-to-date basis. Helps identify where to focus energy management efforts, and enables setting realistic energy management goals.
Utility bill audit These Motors@Work alerts identify potential issues with your utility bill that warrant additional attention prior to authorizing payment. Utility bill audits can also identify potential energy efficiency and conservation opportunities.
Utility provider The electric utility that provides service and/or bills you for power (demand) used and electricity consumed.
Utility rate The tariff, or rate, that describes the type of service your utility provider supplies and what you, as their customer, pay for their services. The simplest utility rates are flat, charging one rate for energy consumed and power drawn regardless of when the customer requires power. Tiered rates charge more for higher demand and energy use. Time-of-use rates charge varying fees based on the day of the week and time of day that the customer draws power and consumes energy. Some rates also charge based on power factor, or the quantity of reactive power (kVAR) a customer injects into the grid as a proportion of total energy used (kW).
Utility rate schedule An internal Motors@Work table that converts a time-of-use rate schedule into SQL for internal application use.
Utility rate structure An internal Motors@Work table that converts a tiered rate schedule into SQL for internal application use.
V
Volume of fluid displaced = Pump Discharge Flow Rate (m³/h) × Operating Hours (hrs.)
Voltage rating The voltage a motor expects to receive. Motors are designed to operate most efficiently at their rated voltage, but will operate effectively over a range ±10% of rated. For example, a motor rated for 460 V operates effectively from 414 V to 506 V, but most efficiently at 460 V.
W
Wired For The voltage which a motor is wired to receive. If a motor is rated to operate at only one voltage, Motors@Work automatically populates the Wired For voltage; however, when a motor is a dual-voltage motor (e.g., rated for 230 V / 460 V), the user must select which voltage the motor is wired to receive.