ELECTRIC TRANSMISSION DELTA /WYE and SERIE/PAPALLEL stator

this chinese seller looks identical to the one flip found, but sells the latching relays in pairs, 3 hours left
http://cgi.ebay.com/2-PCS-12V-coil-pola ... 031wt_1165

edit: found this while looking for caps.
http://cgi.ebay.com/ebaymotors/Automotive-Relay-12V-40A-SPDT-SCB-1-P-1240-3-pcs_W0QQcmdZViewItemQQ_trksidZp1742Q2em153Q2el1262QQ_trksidZp1742Q2em153Q2el1262QQ_trksidZp1742Q2em153Q2el1262QQ_trksidZp1742Q2em153Q2el1262QQcategoryZ50459QQihZ026QQitemZ390041218128#ht_3846wt_1197
 
Just to review that 9C motor:


I acheived few times power burst up to 2900W with my the 9C motor in DELTA mode without significant heat increase...

Outdoor temp was 6 degree C

Average power : 1300W

Motor side cover temp: around 40 degree C when touching it


Doc
 
karma said:
nice doc. did a test with a motor with heaver winds in delta the phase wires get hot :twisted: but the torque is amazing. your going to have fun with the x5 :wink:
Click to expand...


X5 + DELTA... = Hmmmmmmm! :twisted:

Doc
 
This could be a cheap alternative if they are willing to ship 1
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=360-2100-ND
S832.jpg


I have been digging for hours for a proper relay but the only one I found was 8000$

Auto relays would work but when one fails it will throw the whole motor out when you try to switch again. A single 3pdt relay is more reliable and won't wreck your motor.

Has anyone found any? I couldn't find anymore even on ebay
 
caleb7777 said:
This could be a cheap alternative if they are willing to ship 1
http://search.digikey.com/scripts/DkSea ... 60-2100-ND

I have been digging for hours for a proper relay but the only one I found was 8000$

Auto relays would work but when one fails it will throw the whole motor out when you try to switch again. A single 3pdt relay is more reliable and won't wreck your motor.

Has anyone found any? I couldn't find anymore even on ebay
Click to expand...

Wow...I was looking every where to find a 3PDT that can carry at least 30AMP... (I which I could find what DoctorBass got...for the price he paid ;) )

I think this is the best cheap and small solution so far! Thanks you!

Robin
 
I think those 60 latching relays off eBay look nearly ideal, but you need a control circuit to drive them. This kind of circuit should be pretty simple. They look like they are made to be board mounted anyway. I could imaging doing a circuit board that holds 6 of these and has the logic to properly time the impulses to make sure all the contacts open before closing in the new configuration. The circuit could be as simple as a 4P3T switch and a few resistors and capacitors.
 
So I understand that switching from delta to wye when at full speed can destroy a controller because the induced voltage will be about 1.72 times the pack voltage at that point. But what if you had a geared motor? You wouldn't have the bikes weight in kinetic energy that would be converted back into electrical current, you would just have a couple pound motor. Would the voltage spikes be enough to do anything with a geared motor, or should you be safe?
 
The safest way is to have a controller rated 1.8-2x battery voltage, then no matter what happens it won't blow. The other possibility is to make sure the delta->wye transition occurs under the rpm where the wye connected BEMF equals battery terminal voltage.
 
Mine did not blow because of that.

I switched with a 12 mosfet 4110 comtroller (rated 100V fets) and i was using 65Vdc total battery

I switched from WYE to DELTA no problem at full speed..

The thing to be carefull with is to switch back to WYE and ensure that the BEMF is under the fets max voltage...to not blow them

That occured on this video: but the controller protected itself and shuted down(a reset make it working again)

http://www.youtube.com/watch?v=p3mm4hMAHwU


I blown it two times since operating the delta wye method. One simple reasons:

Operated it at very low speed still in DELTA mode

and because of that the phase current was too high.. a way too high! and it blown.

My recommandation.. NEVER USE DELTA TO START YOUR ACCELERATION OR ON HILL...

Switch DELTA ONLY when the current while accelerating is decreased suffisently (when the BEMF reach the Battery Voltage)

Doc
 
CNCAddict said:
The safest way is to have a controller rated 1.8-2x battery voltage, then no matter what happens it won't blow. The other possibility is to make sure the delta->wye transition occurs under the rpm where the wye connected BEMF equals battery terminal voltage.
Click to expand...


I totally agree with you on that :wink:

Doc
 
Thanks for this idea, Doc. I've just used it to convert an RC motor from delta to wye and tested it tonight. It works very well indeed. In that case it lowers the Kv, increases Kt and makes the reduction gear problem a lot simpler.

I posted about it in the "RC motors with hall sensors" thread.

Jeremy
 
Man.... This has really got me thinking. On my motorcycle conversion, I've been planning to use (and already bought) an ETEK-RT brushed motor with Kelly controller (limited to 200 amps max) - running off of four, 60V BMI packs. I went with the RT as I needed something with a lot of torque to deal with the hilly terrain I have here.

However, now you guys have got me thinking of using the ETEK BLDC ME3001, running at 48V with a 120V Kelly brushless controller.

The tough part would be to find a 3PDT contactor or switch that could handle the amps.......

Just out of curiosity - If I was pulling 200 amps from my batteries, how does that translate to the three phase wires in a brushless system? Does each draw 200 amps, or is the load divided by three, with 66.66 amps per phase wire?
 
karma said:
divided by three :)
Click to expand...
Wrong.

The controller has to output a voltage greater than the motor's BEMF to be able to pump current into it, and the voltage difference needed to pump your desired current into it is proportionnal to the system's resistance. So more resistance = more extra voltage output from the controller to achieve a given current and a given motor speed. A controller works by converting it's input voltage times current into a different output voltage times current.

Example: if you are pulling 100V and 200A from your batteries, but your motor is turning somewhere around half of full speed, and thus is creating about half it's max BEMF. So the controller converts this 100V/200A into something like 50V/400A in this situation because that's what the motor needs at it's speed (actually maybe more like 60V/340A minus losses). In this situation you have 340A circulating in two of the three motor wires at a time (so each wire has 340A for 2/3rds of the time). Lower speeds would make for even more motor current.

However, be aware that kelly controllers are rated by phase (motor) current, and not battery current like regular ebike controllers.

Doc learned this the hard way by killing two controllers during his delta tests, since the delta will demand more current at the same speed when compared to a wye.
 
Another option for 'remote' switching - that would be purely mechanical - would be to use a couple of these switches in parallel.

S833.jpg


String them together like this.......

3PDTdoubleswitch.jpg



... with the cable controlled by a three speed, thumb trigger gear shifter.....

16601sram_xl.jpg


"First" gear would be the WYE, "Second" would be 'neutral' (off on the switches), and "Third" gear for the DELTA.

.
 
caleb7777 said:
Here is one but you need 120v ac to flip it. This is an impulse relay (latching relay)

http://www.perfectpoolandspawarehouse.com/ProductDetails.asp?ProductCode=LEG4101250

LEG4101220_s.jpg
(image not accurate, pic for dpdt)

Details of same part#
http://www.gpspool.com/customer/gep...a/2004SpaSourcerCat_319-350_Relay-Suction.pdf

I just found a 40A 3pdt normal relay for 50$, very small, looking into it
Click to expand...


I ordered 2 of the so called 40 amp relays will get back to you, I fixed the links from that post also
JQX38F3Z-24.jpg
 
still not clear on the specs for the relay you have selected.

Crystalyte made motors that had a tapped WYE winding. i used ONE of these relays:
KUMP-14.jpg
View attachment KUKUPDS.pdf
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=PB468-ND

to switch between the taps on the windings. the motor was a front wheel Crystalyte 408/4012 (4012 tapped at 408 for dual speed) on a 48V 30A system. yes i know that the contacts are only rated for 15A but they survived years of pretty much daily use on my trike.

relay contacts can carry much higher currents once contact is made. the rateings are also for pretty much continuous use. they can usually handle higher currents for a fewer number of switchovers.

on a different bike i used 3 of the regular Bosch automotive 40/60A relays. they also worked fine. i found that what fails is the contact if anything. the coils are pretty reliable. and the only contact that failed was one on a super cheap relay i bought on eBay. i donated the rest of that box of relays to the local high school to use in their shop classes. that darn "cheap gene" is gonna kill me one day.

that being said, i was also not pushing 100V at a gazillion amps through the darn things. i was using them sanely on a daily driver. i suspec they will also work on a regular system. i doubt if they will work wellor long on an "Insane-a-cycle". for those guys you better start looking on ebay for some aircraft grade sealed contact, inert gas filled contactors (like the ones DoctorBass has) at a reasonable price.

SSR's won't be much help either. to pass continous amounts of power they would have to be mounted to a heatsink. just like any high power semiconductor. typically for 40A they would need to dissipate 50W and they would be running at 105C. that is hotter than boiling water. that would be pretty hot to the touch. and that would be on a large heatsink.
ssr%20on%20heatsink.jpg

just where would you mount 3 of these?

rick
 
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