Now think about your children and the way they're being exposed to a very serious amount of noise each day, at home, while gaming or watching TV, on their way to school and in the school as well. This way, you can monitor the listening conditions for your children and students and prevent the exposure to excessive audio levels for a healthier life. Insulated-gate bipolar transistors (IGBTs) require full protection to avoid damage and failures resulting from conditions such as short circuits, overloads and overvoltages.
Maryland's Premier Residential and Commercial Electrician Also Serving Northern Virginia and Washington, D.C. Today’s average home is filled with thousands of dollars’ worth of sensitive electronic appliances: televisions, computers, gaming consoles, and much, much more.
Surge protection from TriStar Electric can help protect your home, and your sensitive electronics. TriStar Electric employees are highly trained and experienced with these types of installations, and will perform the service quickly and accurately.
If you are interested in learning more about Surge Protection, please contact TriStar Electric by calling 410-799-5791 or 301-384-8880. There is now a way to help you and your children voluntarily listen to audio content at health-risk levels: the Hamilton Electronics Guardian headphones. In the opposite case, when the audio being played back reaches a level which is too high for safe listening, the green LED shuts down and a red one takes its place, warning about the situation. At the same time, the Guardian headphones from Hamilton Electronics help educate the small for a healthier way of life from the early days, helping them control better the volume of what they are listening to and why not, set an example for the others.
That's why we thought it would be a good idea to create an email address for you to help us a little in finding gadgets we missed. Using these devices together with feature-rich gate drivers, you can implement a cost-effective yet full IGBT protection scheme.
The protection is key to ensuring safe and stable power-converter operations in applications such as motor drives and solar and wind power generation systems. Without the right protection, these appliances are at risk and can be damaged by a powerful surge resulting from an electrical storm or system malfunction.
Our electricians will review your home’s main electrical panel and electrical devices and recommend surge protection solutions accordingly. Interesting links are bound to be posted with recognition going mainly to those who submit.

To detect over-current and overload conditions, isolation amplifiers featuring fast response or fast fault feedback can be used on the output phases and the DC bus.
The solution: main panel surge protection, which protects the whole circuit box, not just individual circuits.
We will review each possible solution with you and ensure that you are well informed to help you make your final decision. They are those long white rectangular boxes with several electrical sockets that allow you to host multiple devices at one time without taking up multiple outlets. Then, if a power surge comes through the line, the power strip will cut power to all devices and prevent serious damage. However, power strips are just one form of surge protection (technically secondary surge protection) and they are not enough to protect your entire home. It consists of an inverter that converts the DC bus voltage to AC power at a variable frequency to drive the motor.
These power devices must operate at a high frequency and must be able to withstand high voltages. 2.), work in conjunction with shunt resistors to provide accurate current measurements in power converters even in the presence of high switching noise.
When used with a resistive divider, iso-amps work as precision voltage sensors to monitor the DC bus voltage. The current and voltage information from the iso-amps are collected by the microcontroller, which uses the data to calculate the feedback values and output signals needed to provide effective control and fault management in the power converters.
To meet this demand, IGBT gate drivers (such as the ACPL-332J [1]) and current sensors with protection features have been introduced to carry out essential fault detection in addition to their driving and sensing functions.
These products provide a cost-effective scheme to implement IGBT protection and eliminate the need for separate detection and feedback components. Refer to References [1, 2] for details of those protection features integrated with gate drivers and how to use those features in IGBT protections.
The shunt + iso-amp current sensing devices on the output phases and DC bus provide fault detection in addition to current measurement.
Within this limit, the fault must be detected, fed back to controller and the shutdown procedure completed within this period. That allows the iso-amp to capture transients during short-circuit and overload conditions (Fig.

The signal propagation delay from input to output at mid point is only 2 ms, while it takes just 2.6 ms for the output signal to catch up with input, reaching 90% of the final levels. Also available are the ACPL-C79B, which offers a higher-precision gain accuracy of ±0.5%, and the ACPL-C790, which has a ±3% gain tolerance.
These features are delivered in a stretched SO-8 package that has a footprint 30% smaller than the standard DIP-8 package.
Nuisance tripping is a false triggering of the fault detection in the absence of any apparent fault condition that will damage the IGBTs. The advantage of this method is that the rejection is independent of amplitude, which means the fault threshold can be set to a much lower level without increasing the risk of nuisance tripping. The outputs of these comparators are connected to blanking filters with a blanking period of 2 ms, and then sent to the Encoder block.
The delay between the fault event and the output fault signal is the sum of the propagation delay and the blanking period (2 ms), resulting in an overall fault detection time of 3.4 ms (Fig. The time period of the allowable overload rating is dependent on the interval of time before the problem of overheating becomes an issue. The ABSVAL circuit rectifies the output signal, providing an output signal proportional to the absolute level of the input signal according to: This output is also wire OR-able. When three sinusoidal motor phases are combined, the rectified output (ABSVAL) is essentially a DC signal representing the RMS motor current. This DC signal and a threshold comparator can indicate motor overload conditions before damage to the motor or drive occurs (lower right portion of Fig. This high voltage is added to the DC bus voltage and forms a very high surge applied to the IGBTs.
A designer needs to scale down the DC bus voltage to fit the input range of the iso-amp by choosing R1 and R2 values according to appropriate ratio. Hong Lei Chen and Chun Keong Tee, “Using gate drive Optocouplers in IGBT protections,” EETimes Europe, December 2010, pp.

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