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What are the two polarities used with direct current welding?
reverse polarity and straight polarity The answer is right but a bit of furthur explanation is required. Polarity can be changed in DC output welding sets. The heat of the welding arc is concentrated on the positive terminal. So when thick plates are welded as more concentration of heat is required on the job the job is kept +ve ie. straight polarity is used. For thin plates concentration of heat is on the filler rod ,so reverse polarity is used.
Can small permanent magnet motors be reverse direction if the direction of current flow to the motor is reverse?
Permanent magnet field motors. With a these motors, a permanent magnet is used to replace the field coil. DC power is connected via the brushes, to the armature only. Reversing the polarity, will cause the motor to reverse its direction of rotation. It is very common to use a switch to intentionally reverse to the polarity, to allow reversal of the motor if desired.
What are the effects of reverse polarization in electronics?
When a magnet's polarity is reversed, the changing magnetic lines of force cutting across wiring induces a voltage in them. This principle is used primarily in motors. Or perhaps this refers to applying DC power to a device in reverse polarity by mistake. If the device is well designed, it will have a safety diode in the power input area to prevent damage, but if the diode is not present, reversing the power polarity will probably destroy every semiconductor junction in it.
What polarity is used for stick welding?
Reverse. Using a D C machine, electricity travels from the negative post to the positive post. Connecting the electrode holder to the positive post and the ground clamp to the negative post means the current flows from the work to the electrode - reverse polarity. In A C machines it doesn't matter which post the electrode holder is connected to.
What is reverse polarity in welding?
This is applicable to DC supply Arc Welding.In Layman language, when the electrode is given positive potential and the work piece is given negative potential, the weld formed is shallow and wide, this method is called 'Direct Current Reverse Polarity' (DCRP) welding procedure.When the machine is set on straight polarity, the electrons flow from the electrode to the plate, concentrating most of the heat on the work. With reverse polarity, the flow of electrons is from the plate to the electrode, thus causing a greater concentration of heat at the electrode. Because of this intense heat, the electrode tends to melt off; therefore, direct current reverse polarity (DCRP) requires a larger diameter electrode than direct current straight polarity (DCSP). Notice that DCSP produces a narrow, deep weld. Since the heat is concentrated on the work, the welding process is more rapid and there is less distortion of the base metal. Overall, straight polarity is preferred over reverse polarity because you can achieve better welds. DCRP forms a wide and shallow weld and is rarely used in the GTAW process. The exception to this is when it is used to weld sections of aluminum or magnesium.DCRP has excellent cleaning power that results from the action of positive charged gas ions. When these gas ions strike the metal, they pierce the oxide film and form a path for the welding current to follow. This same cleaning action occurs in the reverse polarity half of an alternating current welding cycle.
What are the application of straight polarity arc welding?
AC (Alternating Current) and DC (Direct Current) is used to describe the polarity of the electric current that the welder generates and in what direction it travels. If you use the wrong polarity for a certain welding rod, your weld strength will not be very good. The general terms associated with polarity are reverse polarity and straight polarity. These are common to the welding trade. Another way to describe the two terms are electrode positive and electrode negative. Electrode positive is the same as reverse polarity. Electrode negative is the same as straight polarity. Hence the + and the - written on your welder where the cables connect to it. Any type of welding rod you buy will be labeled as to what polarity should be used for welding with it. Using the correct polarity will ensure the proper penetration and the over all look of the final bead. If you use the wrong polarity you can tell by the signs. There will be an excessive amount of spatter, you will have bad penetration, and you will have less control of your arc. Some welding machines have a switch to adjust the polarity. If your welder doesn't have one you will need to switch the welding cables around where they plug into the machine. If you want reverse polarity, you need to make sure the electrode holder is plugged into the + terminal. The easiest way to tell if you are using the wrong polarity is by the sound and the feel of the weld you are laying down. If you don't have much experience with stick welding you will have a little more trouble determining the difference. I have seen guys weld all day long with the wrong polarity. Then I would grab their welder to use for couple of minutes and I could tell right away. It all comes down to experience.
What is reverse polarity-?
Reverse polarity is the opposite of normal polarity. Normal polarity in electronics is when you have the positive hooked up to the positive terminal and the negative to the negative terminal. Reverse polarity would be having the positive hooked up to the negative terminal and the negative to the positive terminal. The same concept can be used with magnets.
What is the use of Reverse String in C program?
The use of the reverse string in C program is used to reverse the letters in the string. An example would be reverse me would be reversed to em esrever.
What rule is used to find out polarity of a current carrying solenoid?
To determine the polarity of a current-carrying solenoid, use the right-hand grip rule. Point your right thumb in the direction of the conventional current flow in the solenoid coil (from positive to negative) and wrap your fingers around the coil in the direction of the current. Your outstretched fingers will then indicate the polarity of the solenoid: the tip of your fingers shows the north pole, while your palm indicates the south pole.
Can we use DC motor at home?
It would depend on what you are using. A direct current motor has a negative and positive terminals. If connected with the wrong polarity - red on black, black on red it will go into reverse possibly causing damage. Car batteries are used as dc. A lot of small appliances may be dc. Best to check the item you are using and connect the right polarity whether it's AC or DC.
What instrument is used for polarity?
a ruler
How do you reverse the polarity of a compass that is 180 off?
Well, the easiest way to reverse the polarity of a magnet is to just turn it around. However, inside of every piece of steel, there are magnetized pieces that will make the steel an induced magnet when a magnet is placed on or by the steel. By putting the oppositely polarized magnet on or by the same steel, you may be able to reverse the magnetism of the steel. Or by making it a core of a coil in which direct current flows in such a direction as to re-polarize it
