0
To prevent wire corrosion. Most phone wire is copper, and it is stripped and exposed to air at many points along its path from the telephone company central office to your phone. Also, breaks in insulation could expose small parts of it to water or soil. Any of these will allow the wire to corrode, and the usual methods of corrosion are that copper in the wire is converted to copper oxide or copper carbonate. Both of those happen as a chemical reaction where copper atoms act as positively charged ions to combine with negatively charged oxygen or carbonate ions in water or dirt. A wire with a positive charge will actually draw the negatively charged ions to the wire and will greatly accelerate corrosion. A negative charge will repel the corrosive ions and will slow the corrosion.
A negative charge will cause some copper to be lost due to a process called electro-deplating (reverse of electroplating), but the rate of copper loss is much less than would be caused by copper corrosion with a positive charge.
The phone company power supply acts like a giant battery. They ground the positive site of the supply so that any part of the system has a voltage that is zero or negative, so the whole system resists corrosion better and lasts longer.
Wiki User
∙ 13y ago
Add your answer:
Earn +20 pts
Why telecom equipment used 48v?
48 volts is a convenient safe voltage to use, and telephone systems use a positive earth connection to minimise electroytic damage ot cables.
Why be use the -48 volt for bts?
48 is volt scale and negative voltage is used for safety of media, to prevent attanuation and noise.
What can a 48 volt power supply be used for?
A lot of commercial telecommunications equipment runs on 48 volts. There are also relays that use 48 volts. I'm sure there are many other uses for this. I'm not aware of any in a typical house, if that's what you're looking for. Perhaps certain water softeners, sprinkler systems, etc. run on 48, but the ones I've seen usually run on 12.
How many volts to run a 48 Volt club car electric motor?
If a 48 Volt club car electric motor requires 48 volts, then it should be given a 48 volt power source, or something close to it. Too many more volts and it may burn out; not enough volts and it may not run or it will try to draw too much power and burn out the power supply.
How do you increase Speed on a Yamaha 48 volt golf cart?
You can increase the speed of an Yamaha 48 volt golf cart by installing a larger motor or more powerful batteries. This will produce more power to the wheels and more speed.
Why plus 24 volt is used for telecom equipments?
+24 volts is not normally used for telecom equipment. -48 volts is the usual value. 48 was chosen as a compromise between safety and voltage/power efficiency. Minus was chosen over plus to manage corrosion effects of cabling in underground installations.
How is -48V possible in telecomm equipment?
Voltage is dependent on a reference. If I have a 12 volt battery, and ground the - side, it is 12 volts to ground. If I instead ground the + side, it is -12 volts to ground. -48 volt telecom equipment is simply referenced to ground "upside down" or backwards, giving it a negative sign.
Why telecom equipment used 48v?
48 volts is a convenient safe voltage to use, and telephone systems use a positive earth connection to minimise electroytic damage ot cables.
Why be use the -48 volt for bts?
48 is volt scale and negative voltage is used for safety of media, to prevent attanuation and noise.
What is negative 48 volt DC voltage?
Negative 48 volt DC voltage is simply a voltage that is negative 48 volts with respect to ground. This voltage is widely used in telecommunication systems.
Can you use a 12 volt battery to charge a 48 volt battery?
No
Can a 36 volt battery charger charge a 48 volt system?
No.
How do you install 12 volt lights on 48 volt cart?
If your cart has 4, 12 volt batteries in series to make up the 48 volts, just connect the 12 volt lights across one of the batteries.
What can a 48 volt power supply be used for?
A lot of commercial telecommunications equipment runs on 48 volts. There are also relays that use 48 volts. I'm sure there are many other uses for this. I'm not aware of any in a typical house, if that's what you're looking for. Perhaps certain water softeners, sprinkler systems, etc. run on 48, but the ones I've seen usually run on 12.
Is 24 volt DC is equal to -48 Volt DC?
No. The value and polarity are different.
Why -48 VDC supply used in telecom equipments?
It was originally supplied by a large bank of lead-acid batteries, 24 cells in series gave 48V.
Where are the positive and negative posts in a 48 volt system?
their are many many types of 48 volt systems you need to show or state more info on your system
