book on synchros/resolvers
in [Design]
|
From: JosephKK on 29 Apr 2010 00:10 On Wed, 28 Apr 2010 07:19:16 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >On Tue, 27 Apr 2010 21:30:34 -0700, Tim Wescott <tim(a)seemywebsite.now> >wrote: > >>JosephKK wrote: >>> On Sat, 24 Apr 2010 07:56:35 -0700, John Larkin >>> <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >>> >>>> On Sat, 24 Apr 2010 03:50:50 -0700, >>>> "JosephKK"<quiettechblue(a)yahoo.com> wrote: >>>> >>>>> On Tue, 20 Apr 2010 04:11:50 -0700, John Larkin >>>>> <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >>>>> >>>>>> On Mon, 19 Apr 2010 20:50:35 -0700, Tim Wescott <tim(a)seemywebsite.now> >>>>>> wrote: >>>>>> >>>>>>> John Larkin wrote: >>>>>>>> Can anybody suggest a good one? >>>>>>> Ha ha ha ha ha he he he he he ho ho ho ho ho aaaaaaaaaaaaaaaaagh! >>>>>>> >>>>>>> (I'm not making fun of you here, that's hysterical laughter). >>>>>> There seems to be some stuff from, say, 1955 or so. I don't suppose >>>>>> much has changed. >>>>>> >>>>>>> Call Renco Encoders and see if you can sweet-talk them out of a copy of >>>>>>> "Feedback Devices in Motion Control Systems", by Robert M. Setbacken. >>>>>>> >>>>>>> Then call Moog Components -- wade through the Moog website and find the >>>>>>> guys that sell the precision industrial and aerospace encoders. Sweet >>>>>>> talk them, too. >>>>>>> >>>>>>> Be aware that all the electronics whizzes who worked on encoders have >>>>>>> died of old age -- it's all mechanical engineers; they know bearings, >>>>>>> they know winding machines, and they know how to test things, but when >>>>>>> you start asking questions about impedance vs. frequency and other >>>>>>> seemingly obvious things the best you'll get is a friendly shrug. >>>>>> Seems that way. A lot of the books and lit seem cartoonish. >>>>>> >>>>>>> They're variable transformers. They're really inefficient. Their >>>>>>> impedance is pretty close to the wiring resistance plus the inductance >>>>>>> times radian frequency (no surprise there). They work over an >>>>>>> astonishingly large frequency range, although they are traditionally >>>>>>> only specified at the frequency that the first customer wanted to use. >>>>>>> The drive amplitude is specified in voltage, although if you read >>>>>>> between the lines they're limiting the I^2R losses in the primary. Try >>>>>>> to ask the guys who design them these days and at best you'll get a >>>>>>> friendly shrug... >>>>>>> >>>>>>> You can order them specified for other frequencies, or sizes, for "some" >>>>>>> NRE. "Some" is relative, and Moog is an aerospace company... >>>>>>> >>>>>>> How tightly are you gonna simulate the resolvers? Just behavioral? >>>>>>> 1st-order with inductances and winding resistance? Parallel >>>>>>> capacitance? Electrical nonlinear effects? Spatial nonlinear effects? >>>>>>> Are you gonna simulate multi-speed resolvers? >>>>>> My gadget is going to be transformers, adcs, dacs, and an FPGA. >>>>>> Whatever I can do with that. I'll be generating low-power signals into >>>>>> an electronics box that thinks it's connected to an LVDT or a synchro. >>>>>> It's representing mechanical positions of things like flaps or bits of >>>>>> engines, so it doesn't need arc-second accuracy. Stuff like >>>>>> multi-speed would be easy. >>>>>> >>>>> Multispeed easy?? Not going to happen. Do you know how to >>>>> elecromechanically zero a multispeed synchro? >>>>>>> There's probably a market for a general-purpose resolver simulator, and >>>>>>> possibly even more so for a general-purpose resolver _meter_ (I recall >>>>>>> looking and not finding one, at a time that one was desperately needed). >>>>>> The meters are around. >>>>>> >>>>>> http://www.naii.com/Angle-Position-Indicators/PSC8 >>>>>> >>>>>> http://www.controlsciences.com/ >>>>>> >>>>>> http://peakelectronics.com/index.php?option=com_content&task=view&id=36&Itemid=62 >>>>>> >>>>> I can see where you think you can break into a lucrative, but niche, >>>>> market. >>>> I don't have to break into a market. A pretty big aerospace company is >>>> asking me to do this to replace a board that they designed themselves >>>> and don't want to/can't make any more. >>>> >>>> A lot of big aerospace companies and national labs used to design >>>> their own electronics. Sometimes it was good, but often not. The trend >>>> is now towards outsourcing, for several reasons. >>>> >>>> John >>> >>> Your last hint, to do multispeed right you also need to be at least a >>> jackleg mechanical or industrial engineer. >> >>I don't see how that's necessary at all, particularly since he's >>planning on doing an all-electronic simulation of a multispeed resolver. > >I hadn't planned to do multispeed, but there's no reason we couldn't. >My first customer is mostly concerned about simulating LVDTs. > >>Perhaps you could say what you have to say, instead of winking and >>grinning and hinting. > >Exactly. He's being way too coy. His record for being actually right >about stuff is right up there with YouKnowWho. [1] > >John > >[1] and I don't mean Voldemort. > The LVDT part is not the same game as multispeed synchro/resolver. But the multispeed synchro game has non-electrotechnolgy parts that majorly affect performance, repeatability and accuracy. That may be where the customer's problem really lies, not in the specifications of the electronic simulator. Though it should impact how it is programmed in realistic test scenarios. Can you say gear train slop?
From: John Larkin on 29 Apr 2010 00:26 On Wed, 28 Apr 2010 21:10:33 -0700, "JosephKK"<quiettechblue(a)yahoo.com> wrote: >On Wed, 28 Apr 2010 07:19:16 -0700, John Larkin ><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: > >>On Tue, 27 Apr 2010 21:30:34 -0700, Tim Wescott <tim(a)seemywebsite.now> >>wrote: >> >>>JosephKK wrote: >>>> On Sat, 24 Apr 2010 07:56:35 -0700, John Larkin >>>> <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >>>> >>>>> On Sat, 24 Apr 2010 03:50:50 -0700, >>>>> "JosephKK"<quiettechblue(a)yahoo.com> wrote: >>>>> >>>>>> On Tue, 20 Apr 2010 04:11:50 -0700, John Larkin >>>>>> <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >>>>>> >>>>>>> On Mon, 19 Apr 2010 20:50:35 -0700, Tim Wescott <tim(a)seemywebsite.now> >>>>>>> wrote: >>>>>>> >>>>>>>> John Larkin wrote: >>>>>>>>> Can anybody suggest a good one? >>>>>>>> Ha ha ha ha ha he he he he he ho ho ho ho ho aaaaaaaaaaaaaaaaagh! >>>>>>>> >>>>>>>> (I'm not making fun of you here, that's hysterical laughter). >>>>>>> There seems to be some stuff from, say, 1955 or so. I don't suppose >>>>>>> much has changed. >>>>>>> >>>>>>>> Call Renco Encoders and see if you can sweet-talk them out of a copy of >>>>>>>> "Feedback Devices in Motion Control Systems", by Robert M. Setbacken. >>>>>>>> >>>>>>>> Then call Moog Components -- wade through the Moog website and find the >>>>>>>> guys that sell the precision industrial and aerospace encoders. Sweet >>>>>>>> talk them, too. >>>>>>>> >>>>>>>> Be aware that all the electronics whizzes who worked on encoders have >>>>>>>> died of old age -- it's all mechanical engineers; they know bearings, >>>>>>>> they know winding machines, and they know how to test things, but when >>>>>>>> you start asking questions about impedance vs. frequency and other >>>>>>>> seemingly obvious things the best you'll get is a friendly shrug. >>>>>>> Seems that way. A lot of the books and lit seem cartoonish. >>>>>>> >>>>>>>> They're variable transformers. They're really inefficient. Their >>>>>>>> impedance is pretty close to the wiring resistance plus the inductance >>>>>>>> times radian frequency (no surprise there). They work over an >>>>>>>> astonishingly large frequency range, although they are traditionally >>>>>>>> only specified at the frequency that the first customer wanted to use. >>>>>>>> The drive amplitude is specified in voltage, although if you read >>>>>>>> between the lines they're limiting the I^2R losses in the primary. Try >>>>>>>> to ask the guys who design them these days and at best you'll get a >>>>>>>> friendly shrug... >>>>>>>> >>>>>>>> You can order them specified for other frequencies, or sizes, for "some" >>>>>>>> NRE. "Some" is relative, and Moog is an aerospace company... >>>>>>>> >>>>>>>> How tightly are you gonna simulate the resolvers? Just behavioral? >>>>>>>> 1st-order with inductances and winding resistance? Parallel >>>>>>>> capacitance? Electrical nonlinear effects? Spatial nonlinear effects? >>>>>>>> Are you gonna simulate multi-speed resolvers? >>>>>>> My gadget is going to be transformers, adcs, dacs, and an FPGA. >>>>>>> Whatever I can do with that. I'll be generating low-power signals into >>>>>>> an electronics box that thinks it's connected to an LVDT or a synchro. >>>>>>> It's representing mechanical positions of things like flaps or bits of >>>>>>> engines, so it doesn't need arc-second accuracy. Stuff like >>>>>>> multi-speed would be easy. >>>>>>> >>>>>> Multispeed easy?? Not going to happen. Do you know how to >>>>>> elecromechanically zero a multispeed synchro? >>>>>>>> There's probably a market for a general-purpose resolver simulator, and >>>>>>>> possibly even more so for a general-purpose resolver _meter_ (I recall >>>>>>>> looking and not finding one, at a time that one was desperately needed). >>>>>>> The meters are around. >>>>>>> >>>>>>> http://www.naii.com/Angle-Position-Indicators/PSC8 >>>>>>> >>>>>>> http://www.controlsciences.com/ >>>>>>> >>>>>>> http://peakelectronics.com/index.php?option=com_content&task=view&id=36&Itemid=62 >>>>>>> >>>>>> I can see where you think you can break into a lucrative, but niche, >>>>>> market. >>>>> I don't have to break into a market. A pretty big aerospace company is >>>>> asking me to do this to replace a board that they designed themselves >>>>> and don't want to/can't make any more. >>>>> >>>>> A lot of big aerospace companies and national labs used to design >>>>> their own electronics. Sometimes it was good, but often not. The trend >>>>> is now towards outsourcing, for several reasons. >>>>> >>>>> John >>>> >>>> Your last hint, to do multispeed right you also need to be at least a >>>> jackleg mechanical or industrial engineer. >>> >>>I don't see how that's necessary at all, particularly since he's >>>planning on doing an all-electronic simulation of a multispeed resolver. >> >>I hadn't planned to do multispeed, but there's no reason we couldn't. >>My first customer is mostly concerned about simulating LVDTs. >> >>>Perhaps you could say what you have to say, instead of winking and >>>grinning and hinting. >> >>Exactly. He's being way too coy. His record for being actually right >>about stuff is right up there with YouKnowWho. [1] >> >>John >> >>[1] and I don't mean Voldemort. >> >The LVDT part is not the same game as multispeed synchro/resolver. Actually, it's about the same. But I wasn't planning to do multispeed just now. >But >the multispeed synchro game has non-electrotechnolgy parts that majorly >affect performance, repeatability and accuracy. That may be where the >customer's problem really lies, not in the specifications of the >electronic simulator. Though it should impact how it is programmed in >realistic test scenarios. Can you say gear train slop? If you ever actually have anything useful to say, then say it. John
From: Jim Thompson on 29 Apr 2010 10:31
On Wed, 28 Apr 2010 21:26:38 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >On Wed, 28 Apr 2010 21:10:33 -0700, >"JosephKK"<quiettechblue(a)yahoo.com> wrote: > [snip] >>> >>The LVDT part is not the same game as multispeed synchro/resolver. > >Actually, it's about the same. But I wasn't planning to do multispeed >just now. > >>But >>the multispeed synchro game has non-electrotechnolgy parts that majorly >>affect performance, repeatability and accuracy. That may be where the >>customer's problem really lies, not in the specifications of the >>electronic simulator. Though it should impact how it is programmed in >>realistic test scenarios. Can you say gear train slop? > >If you ever actually have anything useful to say, then say it. > >John Al Gore snootiness reincarnate :-] ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | The only thing bipartisan in this country is hypocrisy |