Tuesday, October 21, 2014

Daily Photo - Tesla Roadster

Matthew Clayton Such - Tesla Roadster

Electric motor1.5, 2.0 : 248 hp (185 kW), 200·lb·ft/s (270 N·m), 3-phase 4-pole;
2.5 Non-Sport : 288 hp (215 kW), 273·lb·ft (370 N·m), 3-phase 4-pole;
2.5 Sport : 288 hp (215 kW), 295·lb·ft (400 N·m), 3-phase 4-pole
AC induction motor[2]
TransmissionSingle speed BorgWarner fixed gear (8.27:1 ratio)
Battery53 kWh (Lithium-ion battery at the pack level: 117 Wh/kg and 370 Wh/L)

Wednesday, June 13, 2012

Rotary UPS Site Suitability Form

A variety of rotary UPS are available to meet the customer needs. Rotary UPS come in a variety of electrical topologies, power ratings, energy ratings, and physical form factors. This form has been create to assist sales personnel identify important criteria of the customer application so that the appropriate type of rotary UPS can be supplied for the given application. 

Checklist: 

In addition to gathering the information below, obtaining a copy of the proposed single line and any other engineering documentation about the site is very helpful for the application engineering and sales engineering groups.

General Site Parameters:

Existing Facility or New Construction?
Address or coordinates of installation.
Single or Multi-Module installation?
Ambient temperature range of operation?
Transportation/storage temperature?
Relative humidity?
Altitude of facility?
Special Transportation or Logistic conditions?
Transportation or storage conditions, limitations to space or weight?
Special environmental conditions: equipment exposed to fumes, moisture, dust, salt, air,
heat ?
Special mechanical conditions: exposure to vibration, shocks or tilting

Performance limitations regarding, for example, electrical and audible noise
AC bypass circuit requirements
Conditioned space available for remote monitoring system?
IT access available for remote remote monitoring system?

Electrical Input Parameters:

Nominal Input Voltage (V)
Voltage Tolerance band (+/- PU)
Nominal Input Frequency (Hz)
Input Frequency Tolerance band (+/- Hz)
Input Frequency Slew Rate Tolerance (Hz/s)
Input Wiring: Delta or Wye, Number of wires? Wye point grounded or floating?
Number of Input Phases: Single or Three?
Input harmonic current levels at input? (I THD)
Short Circuit current available at input? (A)

Electrical Output:

Type of load; computers, motors, diode rectifiers, thyristor rectifiers, switched type power supplies?
Continous Load Power (kW)
Load Power Factor Number of Output Phases: Single or Three?
Grounding: Earthing of input, output. Solid, LRG, or HRG?
Special features of loads, such as operating duty, unbalance between phases and nonlinearity (generation of harmonic currents)
Maximum step load and load profile
Rated output voltage, steady-state and transient tolerance bands (V or PU, s)
Nominal output frequency and tolerance band
Unbalanced load capability required
Diesel Engine Generator Rating Requirements: (kW)
Supply protection requirements (short circuit, overload, earth faults)

Multi-Module System Configurations:

System Configuration: Redundant or Non-redundant?
Redundant Topology: Isolated, Parallel, Iso-Parallel, other variant?
Switch Type
Synchronization on return of utility requirements

Saturday, February 26, 2011

Energy Generation in the United States

Today, most of the energy consumed in the United States comes from fossil fuels — coal, petroleum, and natural gas, with crude oil-based petroleum as the dominant source of energy. Renewable energy resources supply a relatively small but steady portion, about 8% of U.S. total energy consumption. In the late 1950s, nuclear fuel began to be used to generate electricity, and in recent years has surpassed renewable energy sources.


The use of energy fuels has changed over time, but the change tends to occur slowly. In the long view of U.S. history, wood, a renewable energy source, served as the preeminent form of energy for about half of the Nation’s history. Coal surpassed wood’s usage in the late 19th century, and was, in turn, overtaken by petroleum products in the mid 1900s. Natural gas consumption experienced rapid growth in the second half of the 20th century, and coal use also began to expand as the primary source of electric power generation.

Sources: U.S. Energy Information Administration

Energy measurements




The standard unit of energy in the International System of Units (SI) is the joule (J), equal to one watt second.  One kilowatt hour is 3.6 megajoules.


The kilowatt hour is standard unit of measurement for electrical energy delivered to consumers by electric retailers. 


A "British thermal unit" (Btu) is a measure of the heat content of fuels. It is the quantity of heat required to raise the temperature of 1 pound of liquid water by 1°F at the temperature that water has its greatest density (approximately 39°F).


One practical way to compare different fuels is to convert physical units of measure (such as weight or volume) into a common unit of measurement based on the energy content of each fuel. The British thermal unit (Btu) is a widely used measure of energy content.  Popular physical units of measurement that are converted to Btu are; barrels of oil equivalent, metric tons of oil equivalent, and metric tons of coal equivalent.


It takes between 7,000 to 11,500 Btu of primary fuel to generate a kilowatt hour in a fossil fuel fired power plants. The number of BTUs of heat required to produce a kilowatt-hour of energy in a power plant is referred to as the heat rate of the power plant.  For more information on heat rates see this report: