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need 24V to 115VAC 3 phase inverter for gyro
I've got an ARU 44 gyro and I'd like to power it off my 24VDC system.
It needs 115VAC 3 phase, and about 75W to 100W. Is there an off the shelf unit that can do this, or maybe someone knows of a schematic to build my own? I'm an electronics engineer so I can do this, but inverters are not my specialty so any guidance would be greatly appreciated. |
#2
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need 24V to 115VAC 3 phase inverter for gyro
In article . com,
wrote: I've got an ARU 44 gyro and I'd like to power it off my 24VDC system. It needs 115VAC 3 phase, and about 75W to 100W. Is there an off the shelf unit that can do this, or maybe someone knows of a schematic to build my own? I'm an electronics engineer so I can do this, but inverters are not my specialty so any guidance would be greatly appreciated. WAG says it's probably 400 cycle, as well. not 60Hz. Design can be fairly simple, particularly if you use a micro-controller for the 'logic' of phase generation. start with a clock that is 2 X phases X frequency, Feed it into a counter, that counts from 0 to (phases-1). Hang a number of comparators on the counter outputs, one that triggers for each value. Send each comparator output through a flip-flop. (this gives you a 50% duty-cycle output for each phase, and at the right frequency.) [now for the "analog stuff low-pass filter to sine-wave. Amplify to get the needed voltage/current levels. Voila! The digital part can be hard-wired with several discrete logic chips, or via a cheap micro-processor. |
#3
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need 24V to 115VAC 3 phase inverter for gyro
Hey, for all you folks talking about small transformers and signal diodes to
do the job, note the OP said he needed 75 watts. With normal conversion efficiencies, this is about 4 or 5 AMPS from a 24 volt supply. We ain't in small signal land any more, Toto. Now, to the OP: What makes you think you need that much wattage to spin up a small gyro motor? Jim In article . com, wrote: I've got an ARU 44 gyro and I'd like to power it off my 24VDC system. It needs 115VAC 3 phase, and about 75W to 100W. Is there an off the shelf unit that can do this, or maybe someone knows of a schematic to build my own? I'm an electronics engineer so I can do this, but inverters are not my specialty so any guidance would be greatly appreciated. |
#4
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need 24V to 115VAC 3 phase inverter for gyro
"RST Engineering" wrote in message ... Hey, for all you folks talking about small transformers and signal diodes to do the job, note the OP said he needed 75 watts. With normal conversion efficiencies, this is about 4 or 5 AMPS from a 24 volt supply. We ain't in small signal land any more, Toto. What makes you think you need that much wattage to spin up a small gyro motor? Jim You are correct that the circuit I described will not supply more than a watt or so, but it was enough for my application, which was what I was describing. The original poster said he was an EE, so I did not feel the need to elaborate. If one were to add 3 driver transistors after the diodes (using the 24v Vcc), and be sure to use at least 2 amp (low side) transformers, even this 75 watt load could be supplied. |
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need 24V to 115VAC 3 phase inverter for gyro
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need 24V to 115VAC 3 phase inverter for gyro
The smallest lightest weight way it to do this is to generate 180
volts DC with a high frequency DC to DC converter then use a counter to generate the three phases which drive a six FET three phase H bridge to generate a modified sine wave using the 180 volts DC that you generated with the HF transformer which is much lighter weight than a 400 Hz transformer for the same wattage. This will give you 115 VAC at 400 Hz and eliminates the heavy 400 Hz transformer. John On 29 Oct 2005 01:20:54 -0700, wrote: I've got an ARU 44 gyro and I'd like to power it off my 24VDC system. It needs 115VAC 3 phase, and about 75W to 100W. Is there an off the shelf unit that can do this, or maybe someone knows of a schematic to build my own? I'm an electronics engineer so I can do this, but inverters are not my specialty so any guidance would be greatly appreciated. |
#7
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need 24V to 115VAC 3 phase inverter for gyro
John_F wrote:
The smallest lightest weight way it to do this is to generate 180 volts DC with a high frequency DC to DC converter then use a counter to generate the three phases which drive a six FET three phase H bridge to generate a modified sine wave using the 180 volts DC that you generated with the HF transformer which is much lighter weight than a 400 Hz transformer for the same wattage. This will give you 115 VAC at 400 Hz and eliminates the heavy 400 Hz transformer. John On 29 Oct 2005 01:20:54 -0700, wrote: I've got an ARU 44 gyro and I'd like to power it off my 24VDC system. It needs 115VAC 3 phase, and about 75W to 100W. Is there an off the shelf unit that can do this, or maybe someone knows of a schematic to build my own? I'm an electronics engineer so I can do this, but inverters are not my specialty so any guidance would be greatly appreciated. What heavy transformer? Use an audio transformer. Dan, U.S. Air Force, retired |
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