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All STEMS Products Manufactured by Delta Group Electronics www.deltagroupinc.com

STEMS EMS
The Next Generation in Band-Pass Filters.

Engineers have developed a variety of electronic filters to reduce the effects of unwanted signals (commonly referred to as ‘noise’) on the desired signal. Like fluid filters, electronic filters can be made from a variety of materials, typically including a combination of operational amplifiers, capacitors, and/or varistors. These electronic filters are classified as high-pass, low-pass, and band-pass filters.
High-pass filters block out low-frequency noise, and are often used to prevent low-frequency signals, such as ham radio broadcasts, from interfering with and distorting higher-frequency signals, such as TV signals. Low-pass filters block out high-frequency noise and can be used to minimize the effects of harmonics in inductive motors. Band-pass filters behave as a combination of high-pass and low-pass filters and only allow certain ranges of signal frequency to pass through them.

HOW STEMS WORKS:

STEMS is a highly sophisticated band-pass filter that blocks distortions in electrical power above and below normal signal range.
STEMS blocks out harmonics, power spikes and surges.
STEMS cleans up utility-supplied power to make it better fit the form of a 60-cycle sine wave, forcing current and voltage to conform to that sine wave as well, the ideal design condition for American AC motors.
As a result, motors run more smoothly at lower temperatures, work more efficiently and require less power from the utility.

Put another way, the band-pass effect of a STEMS added to your electrical circuitry will "clean up" your AC power. This creates an ideal operating environment for your equipment, which reduces equipment wear and increases equipment life. This increases power factor, reduces kVAR, amp draw and most importantly, KWH usage.
Remember, you are billed for KWH. Reducing your KWH reduces your electric bills.

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MORE ABOUT HOW STEMS WORKS

In order to understand how a STEMS unit works and why it can reduce your electric utility bill, you need to understand some electrical terminology.

Readers generally fall into two groups, much like a person who buys a new computer. Some don’t care to spend the time to read the manual or acquire an in-depth knowledge of how it works. They just want to turn it on and have it start working. Others like to get a deeper understanding of the product before turning it on. The following information is addressed to this group. It is intended to give you a better understanding of some of the factors involved and how the STEMS unit addresses them.

AMPERES (Sometimes referred to as amps) – This is an indication of the flow of electric current into a circuit (sometimes referred to as the rate of electron flow). This includes both borrowed and used power.

EFFICIENCY – A measure of how well a device converts the power that is purchased into useful work.

Resistive devices convert almost all of the power used to a useful form of energy, such as the heat energy created by an electric heater or stove element or the light energy created by a light bulb. In each case, the losses are very small. Resistive devices are considered to be 100% efficient.

Inductive elements are magnetic devices such as solenoid coils, motor windings, transformers, windings, fluorescent lamp ballasts, microwave ovens, and similar equipment that have magnetic components as part of their design. In inductive devices, such as electric motors, not all of the purchased power is converted into usable energy. A certain portion is lost and is not recoverable because it is expended in the losses associated with operating the device.

Aside from so-called friction losses, and the inherent losses between the rotor and stator, there are other “loss factors” that must be considered. There are losses associated with passing cooling air through the motor. There are also losses from motor surges associated with voltage spikes. Copper and Iron losses are an important consideration, as well. In an energy efficient motor, using a design that employs better grades of materials reduces the losses. Anything that reduces losses will increase efficiency.

KWH – Kilowatt Hour: The basic unit of measure of a residential, commercial and residential electric bill. This is a measure of the amount of power that is delivered. In many respects, the Kilowatt Hour could be compared to a ton of coal, a cubic foot of natural gas, or a gallon of gasoline; in that way, it is a basic energy unit.

KVA – is total apparent power, measured in kilovolt amps. This unit is used instead of using the term kilowatt, when engineers are discussing AC-powered motorized equipment.

POWER FACTOR – The amount of real power that is used, divided by the total amount of power both borrowed and used.

Perhaps the greatest confusion arises due to the fact that early in our science education, we were told that the formula for Watts was Amps times Volts.
This formula, Watts = Amps times Volts, is true for direct current circuits.
It also works on resistive AC loads, such as incandescent light bulbs, and electric range heating elements.

However, when the loads involve a characteristic called inductance, the formula has to be altered to include a new term called power factor. Thus, the new formula for single-phase loads becomes: Watts equal Amps times Volts times Power Factor. The new term power factor is always involved in applications where AC power is used and inductive magnetic elements exist in the circuit. Power factor is expressed as a decimal or as a percentage value.

Values for power factor will range from zero to 1.0. In the case of electric heating elements, incandescent light bulbs and similar resistive power, the power factor is assumed to be 1.0. Power factor can be expressed as a decimal or as a percentage value, but it is usually listed on a utility bill as a decimal.

In the case of electric motors, the power factor is variable and changes with the amount of load that is applied to the motor, the quality of the materials used, and the “cleanness” of the electrical power supplied. Thus a motor running on a work bench, with no load applied to the shaft, will have a low power factor, perhaps .10 (10%). A motor running at full load, connected to a pump or a fan might have a high power factor perhaps .88 (88%).

The term “Power Factor” is difficult to understand. However, the following illustration might help. Utilities have to size their transformers and distribution equipment based on the amount of amperes that are going to be drawn by the customer. Some of these amperes are “borrowed” to magnetize inductive loads within the plant. This “borrowed” power is later returned to the utility company without having been used. This borrowing and returning goes on at a rate of 60 times a second (the frequency of a 60 cycle power system). The borrowed power, as previously mentioned, is used to magnetize such things as electric motors; transformers, fluorescent light ballast, and may other kinds of magnetic loads within a plant. In addition to the “borrowed” power, there is so-called real power. This is the power that is used to produce heat from heating elements, light from incandescent bulbs, and to drive the shaft on motors.

Power Factor is a measure of the relative amounts of borrowed versus real power that is being used within the plant or piece of equipment.

REACTIVE POWER is the non-working power, required to operate the device (measured in kilovolt-amperes-reactive, kVAR). The user is billed for this power, which is the area where the STEMS device provides the most benefit.

REAL POWER – The power actually used to operate the device, measured in kilowatts, kW.

The Kilowatt Hour is not directly related to amperes, and at no place on an electric bill will you find any reference to the amperes that have been utilized. It is vitally important to note this distinction. You are billed for kilowatt-hours: you do not necessarily pay for amperes.

WHY IMPROVE YOUR POWER FACTOR? – There are two primary reasons for improving your power factor. First, you will save money by reducing your power utility bill. Second, you will reduce the equipment wear and waste heat of inductive loads, thereby increasing the service lives of your equipment, which will lower your overall operating costs. Your goal should be to achieve the highest possible power factor in all of your equipment.

Some of the other benefits of power factor improvement include:

• Lower utility bills – Lower power factors require an increase in the electric utility’s generation and transmission capacity, to handle the excessive reactive power demands of the inefficient inductive loads. Utilities usually charge a penalty fee to customers with lower power factors. You can avoid or reduce this additional fee by increasing your power factor.
• Your electrical system’s branch capacity will increase -- Uncorrected power factor requires extra power, which increases demand on your distribution system. Overloading your distribution system’s capacity will cause blackouts (power outages) or brownouts (voltage drops). Excessive voltage drops can cause overheating and premature failure of motors and other inductive equipment.

• Real Power (measured in kilowatts, kW)
• Reactive power (measured in kilovolt-amperes, KVA

• Minimize operation of idling or lightly loaded motors.
• Avoid operating of equipment above its rated voltage.
• Replace standard motors, as they burn out, with energy-efficient motors.

• STEMS blocks spikes, surges and hash, with our patented bandpass filters.
• STEMS enhances power factor with capacitors.
• STEMS reduces single phase line resistance to power returning to the grid.
• STEMS reduces the single and three phase amp draw from the grid.