NZ200978A - Alternator with double wound stator:outputs for welding and mains applicances - Google Patents

Description

200978 Number: 20097 8 Date: 16 June 1982 COMPLETE SPECIFICATION \ POWER SUPPLY APPARATUS I/We, UNIPOWER PTY. LTD.-, of 2 Powell Street, Osborne Park, Perth, 6017, Western Australia, Australia a company incorporated under the laws of the State of Western Australia, Australia hereby declare the invention for which I/we pray that a patent may be granted to me/us and the method by which it is to be performed, to be particularly described in and by the following statement:- 20f978 The present invention relates to a power supply apparatus which can be used to supply power to a welding apparatus as well as for other purposes.

It would be convenient to be able to operate a welding apparatus from the electrical power supply of a vehicle since the welding apparatus could be carried on the vehicle and used at any location.

Vehicle electrical power supplies typically comprise an alternator having an electromagnet and a stator. The electromagnet is energised by having a voltage applied across it. This produces a magnetic field in the region of the electromagnet and upon rotation of the energised electromagnet electric current is obtained from the stator.

In accordance with the present invention there is provided an electrical power supply apparatus comprising an alternator having a rotor and a stator, an output from the stator arranged to be connected to welding apparatus and an input voltage connection to the rotor, the input voltage connection provides a stator output voltage substantially above that provided by a battery to which the alternator is connected, a mains voltage power outlet for operation of mains operable appliances, the stator having first and now amended] ?978 second windings, said first winding being a heavy gauge winding for providing low voltage high amperage alternating current at the output to the welding apparatus and said second winding being a light gauge winding for providing high voltage low amperage alternating current to the mains voltage power outlet, wherein rectifier means interposed between the stator and the output and between the stator and the mains voltage/ power outlet is provided for converting the low voltaae'' high amperage alternating current from the / / 10 first Winding and the high voltage low amperage alternating current .from the second winding to direct current. / ' / / / y Th£ present invention will now be described, by way of example, with reference to the accompanying drawings, in wnich: Figure 1 is an electric circuit of a power supply apparatus; Figure 2 is a schematic illustration of an alternator / winding suitable fox use in a similar circuit to that of Figure 1 to,give an arrangement which incorporates / the present invention; Figure 3 a schematic illustration of a low voltage rectifier used in the above arrangement; 25 Figure 4 is a schematic illustration of a high voltage ...-■n-n 200978 AS A^---J0c-d second windings, said first winding being a heavy gauge winding for providing low voltage high amperage direct t current at the output to the welding apparatus and said second winding being a light gauge winding for providing 5 high voltage low amperage direct current to the mains voltage power outlet, wherein .rectifier means interposed between the stator and the output and Detween the stator and the mains voltage power outlet is provided for converting low voltage high amperage alternating current from the 10 first winding and high voltage low amperage alternating current from the second winding to said direct currents.

The present invention will now be described, by way of example, with reference to the accompanying drawings, in 15 which: Figure 1 is an electric circuit of a power supply apparatus; Figure 2 is a schematic illustration of an alternator 20 winding suitable for use in a similar circuit to that of Figure 1 to give an arrangement which incorporates the present invention; Figure 3 is a schematic illustration of a low voltage rectifier used in the above arrangement; 25 Figure 4 is a schematic illustration of- a high voltage ^978 rectifier used in the above arrangement; Figure 5 is a schematic circuit drawing of a power supply apparatus for use in the above arrangement; and Figure 6 is a schematic circuit drawing of a modification of the circuit of Figure 5.

In Figure 1, there is shown an electrical circuit of a power supply apparatus, said electrical circuit comprising an alternator having an electromagnetic field winding 10 and a stator 12. The stator 12 connections are, as shown, in the DELTA configuration rather than the STAR configuration for increased output with a single winding. The STAR configuration-has been-found to give increased output with a double winding as described hereinafter.

The output from the stator 12 comprises a system of diodes 16 which convert the current produced from alternating current to direct current. The system of diodes 16 comprises three negative diodes 16a connected to earth, three positive diodes 16b which provide the power output and three warning light diodes 16c arranged to nullify a warning light when the system is operating. The warning light is energised by a battery when the alternator is not working.

When the alternator is operating in conventional manner the output from the positive diodes 16b is fed to a battery™* 18 ;4 ;204978 ;through a battery isolating switch 20. The oattery circuit includes an ignition switch 22, a warning light 24, a voltage regulator 26, a multipolar field changeover switch 28 and the field winding of the electromagnet 10. The 5 warning light 24 is energised by current from the battery 18 and nullified by current from the warning light diodes 16c through the multipolar switch 28. ;When it is desired to operate a welding apparatus the 10 battery isolating switch 20 is opened and the multipolar switch 28 switched over so as to be disconnected from the portion of the circuit containing the battery 18 and regulator 26. This action also disconnects the warning light 24 so as to protect it from overload. ;15 ;In this position the switch 28 is connected to a lead 30 from the output from the diodes 16b. A welding apparatus is connected to the output from the diodes 16b via a lead 32. ;20 When the electrical circuit is so connected a small proportion of the output from the diodes 16b passes along the lead 30 to the switch 28 and thence to the field winding of the electromagnet 10. The voltage of the output from the diodes 16b can range as high as 75 volts. The voltage of 25 the output from the diodes 16b can be measured by placing a ;^?N=ri%. ;'• > * ' ' 5N0VI985 / 204978 voltmeter across the earthed lead from the diodes 16c and the output from the diodes 16b. For most purposes satisfactory results are obtained if the alternator speed is sufficient to obtain a voltage of 50 volts prior to 5 commencement of welding. This method is more accurate than tnat of maintaining engine revs using a tachometer as different drive pulley sizes will vary alternator speed in relation to engine speed.

The system can be used whether the regulator 26 is located internally or externally of the alternator. Where the regulator is interally located two additional wires may be soldered to the brushes, which wires then go to the multipolar switch 28.

As an alternative to the lead 30 from the output from the diodes 16b, additional batteries could be connected to the multipolar switch 28 so as to increase the voltage applied to the electromagnet 10 compared to that provided by the 20 battery 18. Alternatively, there could be provided an electronic or capacitor voltage boosting system.

The control system may comprise a plastic cabinet which houses the switch, welding terminals and voltmeter. A 25 manually operable' throttle may be provided and may be 15N0VI985^ $978 attached to the control box to obtain readily the desired alternator output.

As an optional feature there may be provided a power take 5 off from the alternator output in which the voltage is stepped up to a voltage sufficient to operate electrical equipment such as tools, elements and other mains appliances not sensitive to a frequency of 50HZ.

While the arrangement shown in Figure 1 has been shown to work satisfactorily an improved embodiment according to the present -invention is described hereinafter.

In the improved embodiment, the stator 50 of the electrical 15 circuit has, as shown in Figure 2, a double winding in the STAR configuration. The first winding is a heavy gauge winding 52 comprising two parallel dual windings for welding and battery charging purposes. This winding provides a three phase output in the range from 10 to 70 volts with a 20 current typically of 100 to 110 amps.

The second winding is a light winding 54 providing a high voltage three phase power output in the range from 0 to 500 volts with a current typically of the order of 10 amps. 1 5N0V19851 ^978 The output from the heavy gauge winding 52 is fed into a standard low voltage 3-phase bridge rectifier which may be in the form of a diode plate similar to the system of diodes 16 shown in Figure 1. A suitable rectifier for this purpose is illustrated in Figure 3 and is given reference numeral 56. The output from the rectifier 56 is high amperage D.C. current for welding and battery charging purposes.

The output from the light winding 54 is fed into a three phase-bridge rectifier system to produce a high voltage D.C. current.

A suitable rectifier is illustrated in Figure 4 and is given reference numeral 58.

A suitable circuit for utilising the output of the alternator 50 is shown in Figure 5.

In the circuit of Figure 5, the output from the winding 52 passes to the rectifier 56 (not shown) and the resulting positive low voltage D.C. current passes to a positive welding terminal 60. The current then passes to a terminal 61 of a battery switch 62 through which the current passes to the positive terminal of a battery (not shown) via a terminad 63 when welding is not taking place and the °978 terminal 60 is not in use. In this way the battery is charged in conventional manner.

When it is desired to use the output from the winding 52 for 5 other purposes' the battery switch 62 is opened. The current from the winding 52 passes to one half of a socket 64 via a lead 65 from the terminal 61. It also passes to the positive terminal of a voltmeter 66.

The output from the winding 54 passes to the bridge rectifier 58. The negative direct current output from the bridge rectifxer 58 passes to a fuse 68 and then to a double pole switch 70. The double pole switch prevents arcing ot the direct current output when the switch 70 is open.

When the switch 70 is closed the negative output from the rectifier 58 passes to the other half of the socket 64. Also, part of the output from the rectifier 58 passes to the negative terminal of the voltmeter 66.

A lead 72 is connected via the contact 63 with the positive terminal of the battery. The other end of the lead 7 2 is connected to a terminal 73 of a changeover switch 74.

The negative D.C. output from the alternator passes to earth 204978 and is connected to a lead 66 which is in circuit with a negative welding terminal 78. The rectifier 58 is also positively earthed via a lead 79 connected to the lead 76. The lead 76 is connected to a terminal 80 of the changeover 5 switch 74. The lead 76 is connected for earthing purposes to the alternator chassis which is connected to the vehicle frame.

In conventional operation, when the battery switch 62 is 10 closed, current flows into the battery and the battery imposes a voltage limit of the order of 12 to 14 volts (for a twelve volt battery) on the current flowing through the system.

However, for welding purposes a higher voltage of the order of 24 volts is required. In this case the battery switch 62 must be opened so that the battery ceases to influence the voltage of the current flowing through the system.

In the switch 74, in the conventional mode of operation, the terminal 73 is isolated.

A terminal 82 is connected to a lead 84 to the positive side of the rotor of the alternator 50 and a lead 86 to the 25 alternator warning light. It is also in circuit with a ^978 terminal 88 which is also in connection with alternator warning light diodes similar to the diodes 16c of Figure 1 to complete that circuit.

The lead 86 is connected to the battery through the warning light and the output from the warning light diodes nullifies the current from the battery and so extinguishes the warning light. Further, a terminal 90 is connected to the negative side of the rotor. In this condition the alternator 10 regulator (not shown) is also in circuit with the negative side of the rotor. When it is desired to weld using the welding terminals 60 and 78, the changeover switch 74 is switched so as to isolate the terminal 88 and so disconnect the warning light and so as to bypass the alternator 15 regulator. The terminal 82 is connected to the terminal 73 and _the terminal 90 is connected to the terminal 80. In this- condition current flows directly from the battery via the lead 72 to the terminal 73 thence to the terminal 82 and to the positive side of the rotor. Thus, the rotor is 20 energised and the current passing therethrough goes directly to earth through the terminals 90 and 80.

If it is desired to utilise the power output provided by the socket 64 to operate a mains voltage operable appliance, the 25 switch 70 is closed. The voltage at the socket 64 can be 204978 monitored by the voltmeter 66 and, if the voltage is insufficient, the engine speed of the vehicle can be increased to achieve the desired voltage.

In Figure 6 there is shown an arrangement similar to that shown in Figure 5, except that the lead 65 from the terminal 61 is omitted.

The circuit to the socket 64 is completed by a lead 100 from 10 the positive side of the rectifier 58. The lead 100 is in circuit with one half of the socket 64 and also with the voltmeter 66. In this embodiment- the output "from the negative side of the rectifier 58 has to be stepped up to 250 volts to operate mains voltage operable appliances by 15 increasing the engine speed of the vehicle.

Modifications and variations such as would be apparent to a skilled addressee are deemed within the scope of the present invention. For example, it is envisaged that it would be 20 possible to use a dual alternator having two stators and two rotors in one frame giving double the output of the system described above. Also, it is envisaged that the direct current output from the rectifier system could be electronically converted to 50 cycle alternating current to 25 enable the use of 50 cycle sensitive appliances. [now amended

Claims (7)

WHAT WE CLAIM IS: 1. An electrical power supply apparatus comprising an alternator having a/ rotor and a stator, an output from the stator arranged to be connected to welding apparatus and an input voltage^connection to the rotor, the input voltage connection provides a stator output voltage substantially / / above that /provided by a battery to which7 the alternator is 10 connected', a mains voltage power outlet for operation of mains /Operable appliances, the stator having first and second windings, said first winding being a heavy gauge wirraing for providing low voltage /high amperage alternating current at the output to the welding apparatus and said second winding being a light/gauge winding for providing high voltage low amperage alternating current to the mains voltage power outlet, wherein rectifier means interposed between the stator and the output and between the stator and the mains voltage power outlet is provided for converting 20 the low voltage high /amperage alternating current from the first winding and the high voltage low amperage alternating current from the second winding to direct current. 2. An electrical power supply apparatus according to Claim 25 1, in which/the heavy gauge winding and the light gauge X,.. \ * " /• o:\ - 13 - \ ' 5 NOV 3985 200978 WHAT WE CLAIM IS: Ag AMENDED f

1. An electrical power supply apparatus comprising an 5 alternator having a rotor and a stator, an output from the stator arranged to be connected to welding apparatus and an input voltage connection to the rotor, the input voltage connection provides a stator output voltage substantially above that provided by a battery to which the alternator is 10 connected, a mains voltage power outlet for operation of mains operable appliances, the stator having first and second windings, said first winding being a heavy gauge winding for providing low voltage high amperage direct current at the output to the welding apparatus and said 15 second winding being a light gauge winding for providing high voltage low amperage direct current to the mains voltage power outlet, wherein rectifier means interposed between the stator and the output and between the stator and the mains voltage power outlet is provided for converting 20 low voltage high amperage alternating current from the first winding and high voltage low amperage alternating current from the second winding to said direct currents.

2. An electrical power supply apparatus according to Claim 25 1, in which the heavy gauge winding and the light gauge 204978 winding are arranged to provide power for a mains voltage power outlet socket connected to the mains voltage power outlet such that the mains voltage power outlet socket has a voltage across it substantially equal to the sum of the 5 voltage of the heavy gauge winding and the light gauge winding.

3. An electrical power supply apparatus according to Claim 1, in which only the said light gauge winding provides power 10 to a mains voltage power outlet socket connected to the mains voltage power outlet such that the mains voltage power outlet socket has a-voltage across it substantially-equal to the voltage of the light gauge winding. 15

4. An electrical power supply apparatus according to any one of the preceding claims, in which the rotor is energised at all times by current from said battery.

5. An electrical power supply apparatus according to Claim 20 4, in which the heavy gauge winding is also arranged to charge said battery through a switch means arranged to disconnect said battery from the heavy gauge winding.

6. 25 one An electrical power supply apparatus according to any of the preceding claims, in which the alternator is - 14 - 2of978 couplea to a regulator and/or warning light through means for disconnecting same from the alternator.

7. An electrical power supply apparatus substantially as hereinbefore described with reference to Figures 2 to 6 of the accompanying drawings. UNIPOWER PTY. LTD. by their authorized agents, J. D. HARDIE & COMPANY 10 per : — 15 20 25 - 15 - 5N0V1985 j E I H