120v

Found 17 Results for 120v.

Showing 1 to 10.

1. Using An Appliance On Foreign Current
Most U.S. appliances are designed to be used on 110 to 120V ac, 60 Hz current. If an appliance is going to be used on the 220V ac, 60 Hz current found in many European and other foreign countries, the 110V appliance can be coupled to the 220V current through a 2:1 stepdown transformer. These transformers are commercially available, and the same transformer can also be used to convert a 220V foreign-made appliance to 110V domestic current.
http://www.fun-home-projects.com/electrical_projects/​tools/​using_an_appliance_on_foreign_current.html

2. Variable-Frequency AC Power Supply
Occasionally you will want to test European appliances for their performance. Since most equipment from abroad will not operate as intended from standard American 60 Hz 115V outlets, a special power supply is needed for this task. This involves considerable expense which can be avoided by building a variable-frequency ac power supply. This device can produce the 50 Hz output at 115-120V for which most European appliances are designed, as well as provide the 400 Hz output necessary for many power tools. The key component in the circuit is an audio-frequency oscillator with a range of 0-400 Hz (Eico makes a kit suitable for this purpose) whose output is coupled by shielded cable to an audio amplifier. The amplified signal at 72W across 8 ohms places 24V ac across the secondary winding of the 120-24V stepdown transformer. When a load is connected to J (a standard European two-prong receptacle), 120V is induced into the primary. Adjustment of the audio-frequency oscillator to 50 Hz and of the volume control on the audio amplifier for 115-120V output (indicated on voltmeter V) creates the necessary power for foreign equipment.
http://www.fun-home-projects.com/electrical_projects/​tools/​variable_frequency_ac_power_supply.html

3. Shock Hazard
The three-wire electrical service in most homes in the United States was designed to minimize shock hazard. In most foreign countries, a two-wire 200-240V service is provided which increases the shock hazard Although the domestic three-wire service supplies 240V, it also provides 120V. The potential across wires A and C is 240V. But across wires A and B and across wires B and C, the potential is only 120V. Since wire B is grounded, the maximum potential with respect to ground is 120V, not 240V. Nevertheless, there is a shock hazard. If a person touches a defective appliance whose electrical circuit at some point is grounded to its metal case, the person can suffer a lethal shock when standing on a moist floor or touching a grounded object when also touching a metal part of the appliance. Although such an appliance might work okay, it can be dangerous to use and should be repaired.
http://www.fun-home-projects.com/electrical_projects/​tools/​shock_hazard.html

4. Ground Checker
An appliance contained in a plastic housing and which has no exposed metal parts should not be dangerous to handle from the standpoint of electrical shock. On the other hand, a portable power tool such as an electric drill can be dangerous to handle, especially if the user is standing on a moist surface or touches a grounded object, unless the metal case of the tool is grounded through a three-prong power plug. It is now standard practice to equip hand tools with three-wire cords terminated in three-prong safety plugs. Power is transmitted through two of the prongs and two of the wires. The third prong is connected to ground through the electric outlet and its wire is connected to the metal frame of the tool. When there is no three-slot 115V outlet available, the tool can only be connected to the power line through a two-prong to three-prong adapter. The adapter has a pigtail lead which is supposed to be connected to the screw that secures the outlet faceplate. If the outlet box (and faceplate) are actually rounded, the tool case is grounded, making it safe to use. However, when the device has a two-prong plug, it may be dangerous to use if it has ail internal ground. Consider the circuitry of a ground checker that can be assembled in a small minibox. It consists of a small 120V lamp, a DPST toggle switch, a three-hole 115V receptacle (Jl), a Fahnstock clip or binding post (J2), and a two-wire power cable equipped with a standard two-prong plug (P). One side of the 115V ac power line is grounded (by the power company) and the other side of the line is "hot" with respect to ground. To use the ground checker, the appliance is plugged into Jl which will accept either a two-prong or three-prong plug. With P plugged into an ac outlet, either terminal X or Y of Jl will be grounded through the power line, depending upon which way P is plugged into the outlet. When checking an appliance or tool that has a three-prong safety plug, flip switch S from one position to the other. If the third wire of the power cable is connected internally to the metal case of the device, lamp I should light when S is in one position, but not in the other. When checking a device that has a two-prong power plug, connect J2 to the metal case of the device (or other exposed metal part) through a clip lead. The lamp should not light when set to either position. If the lamp does light, there is an internal ground in the device.
http://www.fun-home-projects.com/electrical_projects/​tools/​ground_checker.html

5. Appliance Leakage Tester
A very small leakage current normally flows from the electrical circuit through the insulation material to the exposed metal parts of electric appliances and power tools. Since the insulation material can break down due to age, wear, moisture content, or other reasons, it can allow higher leakage current to flow. This leakage current can become great enough to be lethal to anyone touching the metal surface of the appliance while at the same time contacting a grounded object such as a water pipe, radiator, etc., or when standing on a wet floor. Therefore, it is extremely important that the leakage current of ac appliances be measured before and after servicing or repairing. The leakage hazard is minimized when a three-way power cord is used with the appliance and is plugged into a polarized outlet whose third connector is properly grounded. The effectiveness of this arrangement dep>ends upon the wiring and upon the appliance having a good ground connection. The Underwriters Laboratories and the American National Standards Institute recommend that the leakage current of 120V ac appliances be limited as follows: appliances with two-wire power cords, 0.5 mA; portable appliances with three-wire power cords and third wire grounded, 0.5 mA; nonportable appliances with three-wire power cords and third wire grounded, 0.75 mA. Leakage current can be measured with an instrument such as the RCA WT-540A ac leakage tester. This instrument has no switches, dials, or other operating controls, its black test lead, which is terminated in a clip, is connected to a ground point. The red test probe has a sharp point to enable it to pierce dirt, grease, etc., and is touched to the metal parts of the appliance being tested The meter scale has only one range and is color coded red and green to indicate safe and unsafe leakage levels. If connected to an appliance that has extremely high leakage current or to one that is shorted, an internal fuse will blow. When this happens, a fuse-indicator lamp on the front panel will glow.
http://www.fun-home-projects.com/electrical_projects/​tools/​appliance_leakage_tester.html

6. Portable Hair Dryer
Another type of hair dryer is a portable. This type delivers cool or warm air from a motor unit through a flexible hose into a plastic cap worn on the head. Unlike the salon dryer, it does not provide steam or mist; so has only a motor and a heating element. With the unit plugged into a 120V outlet, and the switch turned to the soft-dry position, only the motor circuit is energized. With the switch in the low position, one element of the heater is energized plus the motor circuit. In the medium position, the other element of the heater is energized plus the motor circuit. And in the speed dry position, both elements of the heater are energized plus the motor circuit. The thermostat is in series with the heater; therefore, if an overheat condition exists, the heater is cut out of the circuit. A fuse on the heater is also provided to burn out if an overheat condition exists. Troubleshooting We can think of this appliance as having two major systems. The heater element and the thermostat make up one, and the motor and impeller comprise the other. The line cord and the switch are common to both. Motor Failure Check the switch and cord set for continuity with an ohmmeter. Check the two leads to the motor fields for continuity. Turn the shaft by hand to detect binding or roughness. The main casting which forms the lower half of the pump body is known in General Electric terminology as the 'orifice." The impeller must not contact the orifice or the pump cover plate. Clearance between the lower edge of the impeller and the orifice should be 0.020 inch. Adjust by loosening the Allen screw at the impeller hub and moving the impeller on the shaft. The screw is designed to grip the round—not the flat—portion of the shaft and should be secured with a dab of Loc-Tite before final tightening. The motorrshould start when plugged into a 95V, 60 Hz powe supply. Heater Element / Thermostat Failure Check all connections to the elements and the elements themselves for continuity. The thermostat should be closed (conductive) when the diyer is cold. The thermostat should open the circuit to the heater elements before the appliance is damaged. To test its action, plug the hose and connect to a regulated 120V power source. The thermostat must cut off before the maximum time listed below for each setting: Disassembly Pull the switch knob and the lever from the adapter. Withdraw the five case screws to release the clip and ring cover. Release the cord strain-relief and remove the wire nut connections to disconnect the cord set. Now you can remove the hose assembly from the case. The orifice with the motor assembly, heater, and thermostat assemblies, together with the switch and impeller, may be lifted from the case. Remove individual parts by disconnecting the wiring and removing the respective mounting screws. Assembly Assembly procedures are self-evident. However, the dryer should be checked for shock hazard. This requires an 1100V power supply. Apply high voltage for 1 minute with the ease cover removed. Test between the orifice and each male-plug terminal.
http://www.fun-home-projects.com/electrical_projects/​repairs/​portable_hair_dryer.html

7. Electric Wrinkle Remover
The electric wrinkle remover heats water internally to make steam. Wrinkles and creases are removed from hanging clothes, drapes, ties, etc. by feeding steam onto them from the spout of the wrinkle remover. Electrically, the unit is rather simple, with a fuse, heating element, and thermostat to control the temperature. Water is added to the tank and heater assembly, and the water, heated to boiling, (forming steam), which channeled through the escutcheon and out the spout assembly. Troubleshooting It the wrinkle remover doesn't generate steam, the fault may be safely assumed to be in the electrical system. Check continuity' of the cord set, fuse, temperature control, and heating element. Blown fuses indicate a short or a defective temperature-control unit. Leaks can develop around the tank-top seal and at the cover assembly. Replace the assembly rather than attempt a repair. Disassembly Remove the lower handle screw and the three base screws. Piill the bottom of the handle out and remove the base by sliding it along the cord set. If it's necessary to remove the cord set, unsolder the lead to the heater wire and remove the flag terminal and sleeve insulation; slide the cord set from the base. Unsolder the fuse from the terminal lead and slide the flag terminal off the temperature control. Remove the sleeve insulation. Now pull the tank and gasket from the handle and body assembly. Discard the gasket (it should not be used again). Reassembly Reverse the disassembly procedure. Use a good epoxy to hold the handle to body if weld breaks. Wet the gasket with alcohol (both inside and outside) as a lubricant. Install the gasket on the tank and insert both together into the body. Final Tests Apply a high voltage of 1200V for 1 second or 1000V for 1 minute between the prongs on the cord set and the tank. (Remove the plug in the base to gain access to the tank surface.) Plug the unit at room temperature into a 120V power source. The temperature control must start cycling within 3 minutes.
http://www.fun-home-projects.com/electrical_projects/​repairs/​electric_wrinkle_remover.html

8. Home Manicure Kit
The electric home manicure kit is only one of several types that are on the market today. The unit consists of a power-pack assembly in the case which incorporates a transformer to step down the house line current to a safe level and a diode to rectify the ac (change the ac to dc). The 15V dc output of the power pack is fed through the terminal board to the cord set and into the power handle assembly. A small dc motor in the power handle assembly is used to power the numerous manicuring attachments. Troubleshooting Two systems are involved: the motor and the power handle. Motor will not run. Check to see that the switch on the manicure set is placed in the on position. Check the plug on the retractable cord to confirm that it is fully seated on the connector pins, and that the "key" on the plug mates with the slot in the case. If these items check okay localize the trouble as follows: 1.  Connect line cord to 120V ac outlet and pull out the retractable cord plug. 2. With a VOM on the 50V dc range, read the voltage at the connector pins. If the switch, cord, and power supply are okay, the voltage should read approximately 15V. 3.  If very low or no voltage is read, disassemble the case as detailed below. 4.  If proper voltage is read, the trouble is in the power handle, which should be tested as shown below. The power handle is subject to two modes of failure. Perhaps the most common is that the handle runs at full speed while the attachments run slow. Clean the attachments in alcohol and relubricate them with petroleum jelly using a toothpick as an applicator. Use very little jelly. Loss of attachments can be remedied by replacing or rebending the bow spring in the slot of the nose piece. Disassembly and Repair The case containing the power supply unit may be disassembled by withdrawing three screws in the deck and one screw in the bottom and lifting the deck. The latch and latch spring may be replaced by simply slipping the spring out of the grooves. If a voltage test with a VOM shows little or no voltage at the connector pins, disconnect the line cord from the outlet and pull out the retractable cord plug from the deck connector. With the blade of a screwdriver, piy and snap "off the shield and insulator fastened to the switch. This will expose the switch terminals. Now with the VOM set on R X 10 ohms range, trace the continuity of the primary circuit from one male prong of the cord set through the switch, through the transformer (95 ohms), the wire-nut connector, and out through the other male prong of cord set. An open-circuit reading will localize the defective part. Snap the metal shield and f ishpaper shroud back onto switch. Next set the VOM on R x 10 ohms range and read the resistance across the deck connector pins. Reverse the ohmmeter leads and read again. This will check the diode in the power pack. One direction should read continuity; reverse direction should read open. If not, the transformer pack is defective and must be replaced. Observe the original color code of all leads. Note: the exact resistance read in the forward direction will depend on the meter used and is not a comparative indication of quality. Caution: continuity and resistance checks must be made with a VOM. Do not use a 110V series light continuity tester or damage to low-voltage components will occur. If the switch or deck is defective, the entire deck and switch assembly may be easily replaced by loosening two screws holding the transformer and two screws holding the connector-pin board. The two leads to the switch terminals should be unsoldered and resoldered to the new switch terminals using care not to drop excess solder into the switch wafer. In reinstalling the connector-pin board, be certain the negative (black lead) pin is oriented nearest to the front edge of the deck. If the voltage test shows full 15V output from the power supply, or if the power supply transformer has been replaced, the following test must be performed. Pull the retractable cord plug out of the socket in the case. With a VOM on- R X 1 range, insert the probes into plug opening. Install the callus-smoother attachment onto nose piece and slowly turn the drum with fingers while watching ohmmeter. Do not spin it fast or developed counter voltage from the motor will give erratic readings. The reading should be approximately 12.5 ohms and at no point in a revolution should it be less than 10 ohms nor more than 20 ohms. If reading is uniformly about 12.5 ohms, the motor is okay. If on the other hand, the reading dips to less than 10 ohms, the motor is shorted. Replace the motor. A reading of more than 20 ohms means a motor segment is open. Replace the motor. If an open circuit is indicated, the cord is defective. Replace cord. As a final check, connect to the appliance 120V ac supply. Insert the cuticle pusher attachment and test for a handle speed of 2000 to 3000 rpm with a vibrating-reed tachometer held lightly against the tip of the cuticle pusher.
http://www.fun-home-projects.com/electrical_projects/​repairs/​home_manicure_kit.html

9. Hair Curlers
One of the most popular of modern home beauty appliances is the hair curler. After the agony of curling irons and permanent waves, tody's electrified approach to hair care is a convenience most women enjoy despite the occasional mechanical and electrical problems which these appliances present. Fortunately, their design allows the do-it-yourselfer to make the needed repairs easily and quickly. The circuit is very simple, employing only a fuse, heating element, and temperature control. The power switch, a microswitch operating from a normally closed position, activates the heating element circuit when the cover of the curling unit is removed. The two indicator lights are energized and remain on until the heating element has reached its optimum temperature (after 3 to 4 minutes). At this point, the thermostat opens to shut off the circuit to the red (heating-indicator) light which lets the operator know that the curlers are ready for use. Temperature is maintained at the optimum level by the thermostat until the cover is replaced. Troubleshooting If the curler is completely dead—no heat and no light—check the switch, line-cord, and connection continuity. The activating tab must engage the switch arm. If the white indicator light is on while the red light remains off and no heat is developed, replace the thermostat. No heat with both lights on means a defective fuse or open heater element. You will have to puncture the fiber-glass sleeve with a probe to check the fuse. With an ohmmeter, check the heater element. If the curler under- or overheats and blows fuses in the process, first check the output temperature (see below). Then replace the thermostat. Disassembly Withdraw the four back screws, and release the top and switch assembly. Disconnect the two spade lugs from the switch assembly. Push the hinge pin and separate the top from the switch and housing assembly. Withdraw the two deck screws located on the extreme right and left sides of the deck. Lift the complete inner unit from the base. Remove the strain relief, slide the sleeve insulation from the spade connector and remove the line cord. Remove the large sleeve insulator. Remove the spade connector from the thermostat; withdraw the thermostat screw and thermostat. Remove the tape and twist nut from the lead wires. Push the red indicator light assembly and white indicator light assembly out of the deck. The lead and connector assembly (heater to pilot light) may be removed from the heater lead. Withdraw the three remaining deck screws and remove the deck. Pry one side of the heater shield away from the side of the casting and slide the heating assembly from the casting. To remove the fuse, it is necessary to remove the flag terminal, slide the fiber-glass sleeve off the fuse, and disconnect the other end of the fuse from the heater lead Reassembly and Repair Reverse the disassembly procedure. The shield must hold the heater assembly firmly against the casting. Rearrange the wiring on all HCD-1 models for service as follows: 1.  Remove the fused-heater lead flag terminal from the temperature control. 2.  Pull the fused-heater lead from under the pilot-light line cord lead, and redress it over the top, reconnecting the flag terminal to the temperature control. Note: A heatsink must be used between the fuse and wire or connector to protect it when soldering. Final Test Apply high test voltage (1100 volts) for 1 minute between each prong on the cordset and the curler plate casting. The wattage must be between 375 and 420W when plugged into a 120V ac power source. The thermostat must cycle with the first cycle taking place within 4 minutes after the switch is turned on. This test must be made in a room temperature of 70°-85°F. Make a test curler by utilizing a standard large curler, XH15X370, and thermocouple wire, XA12X54. See sketch. 1. Melt an indentation in the center of the top of the curler, with a soldering iron, down to the metal. Place the junction of the thermocouple in the indentation next to the metal and melt the plastic around the thermocouple wire holding it firmly in place. (Do not wrap the wire around the curler.) 2.  Connect the thermocouple wire ends to the meter, XA12X57. Place all the curlers in their respective locations and substitute the test curler for the large one on the extreme right in the middle row. 3. Turn the unit on and allow to heat for 10 minutes. The temperature must be between 150° and 180°. 4.   If the unit does not meet this specification, the temperature control must be replaced. (Do not attempt to calibrate the temperature control.)
http://www.fun-home-projects.com/electrical_projects/​repairs/​hair_curlers.html

10. Waffle Irons
The waffle baker has reversible Teflon-coated grids, and is controlled by a thermostat which allows a temperature range of from 210° to 470°F. It is rated at 1200W, 120V ac, which is a typical specification for waffle irons. If the unit is "dead," that is, if it will not heat at all, begin a continuity test with an ohmmeter from one of the male plugs on the line cord step-by-step through the element, thermostat, and back to the other male plug. If the thermostat and heating element both have continuity through them, check for loose or broken connections within the top and bottom shells and in the line cord itself. If the problem is one of not cooking the waffles (or burning them), the thermostat may have to be replaced. First, however, try adjusting the thermostat. Remove the bottom grid, and loosen the set screw on the stop arm. Replace the grid, and determine the temperature with a thermocouple or surface thermometer placed in the center of the grid. With a thermocouple, the unit must be closed for an accurate reading. With a surface thermometer, the unit must be open; therefore, the temperature reading will not corespond with the name-plate specification. Set the control knob at "3" and take a temperature reading after about 6 cycles or when the reading has stabilized. The cycles can be observed by the use of a wattmeter or by the on-off indication of the signal light. The temperature reading at "3" with a thermocouple should be 320-340°F. A thermometer reading should be 240-260°F. If the temperature reading is outside this range, turn the control knob accordingly to obtain a reading within this range. This may take several cycles. Remove the knob insert with a sharp tool for access to the screw securing the knob to the shaft. Then remove the knob from the shaft without moving the shaft and reset the knob at the "3" position. With the top arm in the vertical position, tighten the set screw of the stop arm using Loc-Tite as a sealant. The stop arm limits the rotation of the control knob within range of the name or temperature indicator plate. If a thermostat is replaced or a control knob accidentally removed, a starting position must be determined. To do this, loosen the set screw in the stop arm and rotate the control shaft until an on-off point is found. Install the control knob at the 210°F point and adjust the thermostat as described above. If the heating element is open, you will have to disassemble the waffle baker and replace the element. First, remove the bottom grid. Next, bend the retaining tabs and remove the element shield. Note the position of the control knob before disturbing it. Then straighten the retaining tabs of the element case and lift the element case up and out of the shell. Be careful not to move the control shaft. Note that the element case is slotted to allow the retaining tab to pass. Remove the element from the terminals and hooks. When replacing the element, stretch it so that the coils are evenly spaced for even heat classification. Replace any element hooks which may be cracked or broken. Position the insulating washers at terminals properly to prevent shorting. The upper element must be placed so the glow can be seen through the lens of the signal light. To replace the thermostat, remove the element case (see the preceding paragraph for element disassembly), then the element lead to top shell and the thermostat lead at cord terminal pin. The element case with thermostat can now be removed as an assembly. Pry and slide the outer housing up and out of the case. Remove the insulation pads and the thermostat lead at the element terminal. Replace the nuts on these terminals to prevent damage to insulating washers. Remove the stop arm. Now turn element case on its back and remove the control shaft by turning it clockwise. Catch the loose washer at the thermostat end of the control shaft. Turn the element case over and lift out the thermostat along with the inner housing. Remove the thermostat from inner housing. A silicone lubricant can be used on the threads of the control shaft for ease of operation.
http://www.fun-home-projects.com/electrical_projects/​repairs/​waffle_irons.html


Page 1 2

Search Here:

Menu:
Home
Collecting
Crafts
Electrical Projects
Energy Savings
Hobbies
Home Ownership
Household Repairs