Re: [EVDL] Genset range extender
You really don't care about frequency. All you care about is staying below the maximum allowed battery voltage (or staying below whatever the signal on the BMS says is "to high".) Thus, the generator speed (and the engine speed) can be whatever you wish it to be. Of course, you have to stay below the design limits for the generator rotor speed, but that is typically 3600 rpm or something close to that. Large generators have some sort of field control, so you run the rpm up to the desired amount, then dial up the field current until the generator is either putting out the max current it is designed for, or the voltage has reach the max battery voltage. Conversely, you can set the field current to some fixed value, and run the rpm up until you reach one of the above same limits. Bill D. On 3/6/2018 11:04 PM, George Tyler via EV wrote: He only wants 30 kw, many engine could do this at lower rpm. Low rpm is not a problem as long as it is high enough to keep the oil pressure up and not cause vibration that may cause crankshaft failure. -Original Message- From: "Lee Hart via EV" Sent: 5/03/2018 04:55 p.m. To: "R. Sparks Scott" ; "Electric Vehicle Discussion List" Cc: "Lee Hart" Subject: Re: [EVDL] Genset range extender R. Sparks Scott asked me to post this for him, as he's not subscribed. He wrote: Aside from the worn-out idea that impromptu series hybrids are anything worth bothering with, John needs to know that his *diesel* genset head is intended to be driven by a diesel engine, not a gasoline engine. Why this matters is that all directly-driven generator heads for diesels will be optimized for 1800 RPM at rated output (for 60Hz), while gasoline (and LPG) heads will expect 3600 RPM. Obviously, if he is intending on rectifying the output to DC, it doesn't matter that the head won't need to be on-frequency of 60Hz, but forcing a gas engine to lug along at lower RPMs to make the voltage more-or-less correct is going to be a strain on the ICE and probably give him a big hit in available peak voltage, and by association, available current into his battery pack/motor. My inclination would be to stop encouraging him until he understand the dynamics of what he is proposing. Series hybrids don't work well in the best of designs, and he's throwing together a collection of incompatible components that are sure to disappoint. That's a good point. While I've seen gasoline gensets that ran at 1800 RPM, most do indeed run at 3600 RPM. This makes them smaller (but noisier). Gasoline engines need to run fast to generate their rated horsepower. But if he's driving it with a car engine, most of them will happily run at 1800 RPM for hours on end. You just can't get anything near its rated horsepower. For instance, it might require a "100 HP" engine to produce 30 HP continuously. Projects like this are always a trade-off between the "right" way, and the "expedient" way to do it. Using what you have, in unconventional ways isn't perfect, but may be good enough to get by. ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Genset range extender
He only wants 30 kw, many engine could do this at lower rpm. Low rpm is not a problem as long as it is high enough to keep the oil pressure up and not cause vibration that may cause crankshaft failure. -Original Message- From: "Lee Hart via EV" Sent: 5/03/2018 04:55 p.m. To: "R. Sparks Scott" ; "Electric Vehicle Discussion List" Cc: "Lee Hart" Subject: Re: [EVDL] Genset range extender R. Sparks Scott asked me to post this for him, as he's not subscribed. He wrote: > Aside from the worn-out idea that impromptu series hybrids are > anything worth bothering with, John needs to know that his *diesel* > genset head is intended to be driven by a diesel engine, not a > gasoline engine. Why this matters is that all directly-driven > generator heads for diesels will be optimized for 1800 RPM at rated > output (for 60Hz), while gasoline (and LPG) heads will expect 3600 > RPM. > > Obviously, if he is intending on rectifying the output to DC, it > doesn't matter that the head won't need to be on-frequency of 60Hz, > but forcing a gas engine to lug along at lower RPMs to make the > voltage more-or-less correct is going to be a strain on the ICE and > probably give him a big hit in available peak voltage, and by > association, available current into his battery pack/motor. > > My inclination would be to stop encouraging him until he understand > the dynamics of what he is proposing. Series hybrids don't work well > in the best of designs, and he's throwing together a collection of > incompatible components that are sure to disappoint. That's a good point. While I've seen gasoline gensets that ran at 1800 RPM, most do indeed run at 3600 RPM. This makes them smaller (but noisier). Gasoline engines need to run fast to generate their rated horsepower. But if he's driving it with a car engine, most of them will happily run at 1800 RPM for hours on end. You just can't get anything near its rated horsepower. For instance, it might require a "100 HP" engine to produce 30 HP continuously. Projects like this are always a trade-off between the "right" way, and the "expedient" way to do it. Using what you have, in unconventional ways isn't perfect, but may be good enough to get by. -- You never change things by fighting the existing reality. To change something, build a new model that makes the existing model obsolete. -- R. Buckminster Fuller -- Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA) -- next part -- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20180306/18302a1d/attachment.html> ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Genset range extender
On Sun Mar 04 19:55:19 PST 2018 ev@lists.evdl.org said: >R. Sparks Scott asked me to post this for him, as he's >not subscribed. He wrote: > >> Aside from the worn-out idea that impromptu series hybrids are >> anything worth bothering with, John needs to know that his *diesel* >> genset head is intended to be driven by a diesel engine, not a >> gasoline engine. Why this matters is that all directly-driven >> generator heads for diesels will be optimized for 1800 RPM at rated >> output (for 60Hz), while gasoline (and LPG) heads will expect 3600 >> RPM. yes, I know that. I was actually planning on using a cog-belt pulley to handle the RPM difference. I also know that a home-made series hybrid isn't an especially efficient way to go. I do believe that it will be MORE efficient than driving my 16mpg diesel rig for many trips. It will also be more efficient than using my diesel rig to tow the EV to more distant car shows. >-- >You never change things by fighting the existing reality. To change >something, build a new model that makes the existing model obsolete. >-- R. Buckminster Fuller >-- >Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com -- Tigers prowl and Dragons soar in my dreams... ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] Genset range extender
R. Sparks Scott asked me to post this for him, as he's not subscribed. He wrote: Aside from the worn-out idea that impromptu series hybrids are anything worth bothering with, John needs to know that his *diesel* genset head is intended to be driven by a diesel engine, not a gasoline engine. Why this matters is that all directly-driven generator heads for diesels will be optimized for 1800 RPM at rated output (for 60Hz), while gasoline (and LPG) heads will expect 3600 RPM. Obviously, if he is intending on rectifying the output to DC, it doesn't matter that the head won't need to be on-frequency of 60Hz, but forcing a gas engine to lug along at lower RPMs to make the voltage more-or-less correct is going to be a strain on the ICE and probably give him a big hit in available peak voltage, and by association, available current into his battery pack/motor. My inclination would be to stop encouraging him until he understand the dynamics of what he is proposing. Series hybrids don't work well in the best of designs, and he's throwing together a collection of incompatible components that are sure to disappoint. That's a good point. While I've seen gasoline gensets that ran at 1800 RPM, most do indeed run at 3600 RPM. This makes them smaller (but noisier). Gasoline engines need to run fast to generate their rated horsepower. But if he's driving it with a car engine, most of them will happily run at 1800 RPM for hours on end. You just can't get anything near its rated horsepower. For instance, it might require a "100 HP" engine to produce 30 HP continuously. Projects like this are always a trade-off between the "right" way, and the "expedient" way to do it. Using what you have, in unconventional ways isn't perfect, but may be good enough to get by. -- You never change things by fighting the existing reality. To change something, build a new model that makes the existing model obsolete. -- R. Buckminster Fuller -- Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
