0
What are the possible short circuit current rating of cables for different high voltages?
The short-circuit current rating of a cable is the thermal energy it withstands in the short time (normally berween 0,2 and 3 seconds) a short-circuit holds out, till it is limited by the opening of a circuit breaker or the melting of a fuse. This thermal energy strain is characterized in electrical engineering by the product I2t. It order to make this rating independent of the cross section A of the cable, we prefer to replace I by the normalized intensity strain I/A. The modified thermal withstand becomes now
(I/A)2t. In this form it depends only on the conductor material, inversely on the initial temperature of conductor before the short circuit and directly on the final temperature of conductor after the short circuit. The last two temperatures depend on the material of the cable's insulation and on the normal operating current of the cable. All these are embodied in a factor K so that (I/A)2t=K. We can find values of K in form of tables or formulas in technical literature. According to the international standards, the coefficient K takes on the following values where K [(A/mm2)s1/2]:
- K=115 for copper conductors with PVC insulation
- K=135 for copper conductors with insulation XPLE or EPR
- K=74 for aluminum conductors with PVC insulation
- K=115 for the connections of copper conductors with tin solder
The short-circuit rating of a cable is useful because we must compare this rating with the specific let-through energy I2t of the overcurrent protective device in correspondence with the maximum short-circuit current of the installation. If it is smaller, it is quite possible under short-circuit conditions that the cable will be damaged, although the protective device will open the faulted circuit without damage to itself.
What else can I help you with?
What is Modular Operation Theatre Manufacturers?
Modular Operation theatre is a current idea of operation theatre anywhere all current technology presented to offer best possible surgical care to the patient
3 Different types of operating systems in current use?
Linux, Windows, OSX
How a copper wire is insulated?
There are a number of ways copper wire can be insulated - or has been insulated in the past - but today, the most common insulating material for copper wire (by no means the only one, though), is vinyl/plastic.
How often is Coronation Street shown?
It is on at 7.30 till 8.00 on Monday. Then it comes on again at 8.30 till 9.00 again on Monday. It comes on at 8.30 till 9.00 on Thursday. It comes on at 7.30 till 8.00 on Friday. Then it comes on again at 8.30 till 9.00 on Friday. Thats 5 episodes every week! Hope you enjoy watching them!! :)
How is corporate parenting different from portfolio analysis?
Corporate parenting is choosing an overall direction for a business. Portfolio analysis is looking at all of the current investments and deciding the best course of action moving forward.
Do voltages vary around the circuit and why?
A: Voltages varies on a circuit because current varies caused by difference in resistance
What is different between a series circuit and a parallel circuit?
In a parallel circuit there are multiple possible pathways for the current to flow.
Why you use resisters in your circuit?
To adjust/control/set voltages and/or restrict current.
The electric force that makes current flow in a circuit is related to the what?
The electric force that makes current flow in a circuit is related to the resistance.
What measures the flowing in a circuit?
The flow in a circuit is called the electric current and it is measured by voltages. The number of volts that are present in the charge will determine the strength of the electric current.
What 2 voltages is a short circuit made of?
Circuits are not made of voltages, they are made of loops. A short circuit exists when a connection is added that is not supposed to be part of the intended circuit as designed. This added connection produces extra loops in the circuit that typically prevent current from reaching parts of the circuit where it is needed and can cause excessive current to flow in other parts of the circuit, resulting in damage to the components in the circuit.
When a 10mA forward bias current and the voltages at the anode and cathode of a diode in a circuit are found to be the same what is the diode most likely to be?
With a 10mA forward bias current, if the voltages at the anode and cathode of a diode in a circuit are found to be the same, then the diode most likely to be shorted.
If two light-bulbs are connected in a series circuit and one of the light-bulb's current flowing is 0.5 A what is the current flowing in the other light-bulb?
Current in a series circuit is the same throughout the circuit. Voltages are additive. Voltage in a parallel circuit is the same throughout the circuit. Currents are additive.
What is transient current?
Transients can be currents or voltages. They occur momentarily and fleetingly in response to a stimulus or change in the equilibrium of a circuit.
Why a short circuit happen?
Presumably, the current follows a path (a circuit) to do whatever it was "made" to do. If water, for instance, enters the circuit, a shorter path may develop, and the current will (partially) take the short circuit. Or a wire could become lose and short circuit the intended path.
What kind of circuit is one in which all parts are connected in a single loop?
That is a series circuit, all parts have the same current flowing through, and the voltages add up.
Should current be measured with the power off the circuit?
It will not be possible to measure current unless the circuit is powered and operating.
