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Electric motors typically have a surge (Also called in-rush or start up) current rating. When the motor is not energized it takes added power to start it rotating. This is just like when you step on the accelerator pedal to get your car moving and then ease off on the gas pedal when you get at speed. One rule of thumb is that the surge current may be as much as 6 times the running current.
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Is surge current the same as short circuit current?
Not usually, but it may depend on the context. For instance, surge current might be used for a generator that is going to start a motor. Motors draw high current as they start, then the current drops to a normal level, called RLA, or running load amps. Generators have a watt rating for continuous operation called running watts, but they also have a 'surge' rating. You might see a generator listed as a '6000/5200 watt. The 6000 watts is the 'surge' rating. This means the generator can supply 6000 watts for a few seconds, such as might be needed to start a motor, but cannot supply more than 5200 watts continuously. Short circuit current on the other hand simply means how many amps will flow instantaneously if you drop a wrench across the two wires! For a normal utility power service, the short circuit current, also called fault current, can be several tens of thousands of amps, even though the main breaker is only a couple hundred amps.
What is a surge in voltage or current in an electrical circuit called?
A transient, surge, spike, etc.
What is the difference between an electrical surge and a brownout?
A surge is an over voltage and over current situation and a brownout is an under voltage situation.
What is the current rating of T2L 250v fuse?
The current rating is 2A (2 amps).
Can TVs diode can be connected in series to increase the surge current?
No. By Kirchoff's Current Law, components in series all see the same current.
How do fuses work to prevent fires?
On a current surge that is larger than the rating amperage of the fuse, the link in the fuse melts and opens the circuit thereby stopping the current flow.
Is surge current the same as short circuit current?
Not usually, but it may depend on the context. For instance, surge current might be used for a generator that is going to start a motor. Motors draw high current as they start, then the current drops to a normal level, called RLA, or running load amps. Generators have a watt rating for continuous operation called running watts, but they also have a 'surge' rating. You might see a generator listed as a '6000/5200 watt. The 6000 watts is the 'surge' rating. This means the generator can supply 6000 watts for a few seconds, such as might be needed to start a motor, but cannot supply more than 5200 watts continuously. Short circuit current on the other hand simply means how many amps will flow instantaneously if you drop a wrench across the two wires! For a normal utility power service, the short circuit current, also called fault current, can be several tens of thousands of amps, even though the main breaker is only a couple hundred amps.
What fuse rating do you need for an 11 amp circuit?
A fuse is designed to "open" if the current exceeds the specifications of what it is protecting. I have never heard of an 11 A circuit. If you are trying to protect a device that has an 11 A rating it needs an 11 A fuse. With a lesser rating the fuse will blow whenever the current exceeds the rating and if you use a higher rating it won't protect the device. Also recognize that fuses have different response times to allow some surge current without blowing. For example a skow blow fuse will allow an over-current for a small amount of time before blowing.
What is a surge in voltage or current in an electrical circuit called?
A transient, surge, spike, etc.
Why are surge protectors rated in joules?
Joules is a unit of energy. The rating says how much energy they can absorb in a surge without being damaged. If damaged by a surge you better just throw it out.
What is MCOV rating for lightning arrester?
It is Maximum Continuously Operated Voltage to select the rating of Surge arrester or lightning arrester.
What is the relation between surge current and fault current?
Fault/short circuit current is the available current from the source when a short circuit occurs. It is the maximum current the source can provide, defined as an RMS value, usually without any DC offset. Surge current is the maximum instantaneous current that is drawn by "turning on" or energizing a device such as a motor or transformer. Surge current will be less than fault current. If you assume a very strong source relative to the device rating, the surge current will be solely dependent upon the device in question (so fault current and surge current have no intrinsic connection). For a transformer, inrush may be 5-7 times the self cooled full load rating. Motors are usually less than this, and depending on the starting technique and configuration can be little (20-50%) over full load rating. From these definitions, and the above paragraph, it should be clear that if you have a weak source relative to the device, the device may not be able to draw as much current as it would if connected to a stronger system. If this occurs, the voltage will dip. An example would be a system where the available short circuit power is 600MVA; A 60MVA transformer is connected to this system bus. Energizing this transformer without any sort of controled closing could result in (7) x 60MVA = ~420MVA on inrush. This is relatively close to the available short circuit power (70%), so you can expect the system voltage to dip as a result. If the available short circuit current was around 20,000MVA, energizing such a transformer would not cause any significant system voltage dip.
What is difference between surge absorber and surge suppressor?
There is likely no difference. Neither is accepted terminology for a surge suppressive device (SPD). If these products have been tested by safety organizations such as CSA (Canada) or UL (US) or tested to international surge standards (IEEE, IEC), then they should bare the correct terminology, otherwise, they are not tested to provide protection to equipment during a surge. Surge Absorber acts as a load that utilizes the high current until it exhausts. but the surge suppressor diverts the high current into ground without reaching the sensitive parts of the circuit. Surge absorber degrades faster than a surge suppressor.
What is the difference between an electrical surge and a brownout?
A surge is an over voltage and over current situation and a brownout is an under voltage situation.
What unit of measure is used to describe the amount of work a surge suppressor can do before it stops protecting from electrical surge?
There are 3 items that can be used for surge suppression measurements. Most of the plug in strips use Joules as a measure but this can be very misleading. Joules is a measure of energy. Energy is current (amps) times voltage (volts) times time (seconds) or E=I*V*t. Voltage during a surge is critical in determining if downstream equipment is protected. So low voltage rating are important. Current during a surge is important as this is a measure of how many amps are flowing diverting the surge from the downstream loads. So high surge current rating are important. Time is not generally critical, but is determined by the characteristics of the surge. For standard surge testing, the time is identical for the same waveshape. So Joules appears useful at first glance because it incorporates voltage and current in one measure. However, one can increase the joule rating by increasing the voltage (bad) while decreasing the current (also bad). Joules can also be manipulated by using waveforms that are not standardly used in the industry. So rather than use Joules, it is much better to look at the voltage during a surge and the maximum surge current a product uses and ensure the testing is with a recognized standard surge waveform.
What is a good surge protector I can buy?
When looking for a quality surge protector you should consider the clamping voltage, response time, the energy absorption and dissipation rating, as well as the warranty. Two surge protector that come highly rated in those categories include the APC and Belkin Surge Protectors.
Homeowners buy surge protectors to protect their possessions from unexpected surges of what?
Electric Current
