three speed switch problem (no fast speed)

[jimmyhackers]

hello
bought one of these escs for my mini moto ebike (leccy 14" unicycle hub motor)
https://www.ebay.co.uk/itm/48V-72V-1000W-Brushless-Motor-Controller-Electric-Bicycle-For-E-bike-Scooter/391045522309?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

all wired up and the three position speed switch only does low or high. position 2 and 3 are the same middle speed

i have put one of these escs on my proper ebike (26" wheel) a while ago and i get a defined three speeds 30mph, 40mph 50+mph

the switch is fine, using a peice of wire instead to jump contacts provides the same result.

is my controller broken/faulty?

TIA
jim

 

[Tommm]

hello
bought one of these escs for my mini moto ebike (leccy 14" unicycle hub motor)
https://www.ebay.co.uk/itm/48V-72V-1000W-Brushless-Motor-Controller-Electric-Bicycle-For-E-bike-Scooter/391045522309?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

all wired up and the three position speed switch only does low or high. position 2 and 3 are the same middle speed

i have put one of these escs on my proper ebike (26" wheel) a while ago and i get a defined three speeds 30mph, 40mph 50+mph

the switch is fine, using a peice of wire instead to jump contacts provides the same result.

is my controller broken/faulty?

TIA
jim

Maybe you are confusing common wire with low wire. So while nornal/low speed are correct you are missing high speed.

Also, normal speed is simply not connecting anything.

 

[jimmyhackers]

i tried every wiring config (there are only 4) and i only get normal or low. the correct wiring for high does not work, it just does normal speed when selected.

the switch is not at fault. i also tried using just a peice of wire to bridge pins and it gave the same results.

 

[aroundqube]

So, the next step is to measure for +5VDC from the common negative terminal on the speed wire plug on the controller ( power on ), to the hot wire terminal for position #3- high speed on that plug. If no voltage, follow that hot wire back to the solder pad on the circuit board and measure for +5VDC there. HKSUNWIN has replied helpfully to ES members in the past.

 

[jimmyhackers]

thanks for the help.

both low and high speed wires have 5vdc.

the only thing i can think of is my actual hub motor reaches top speed at mid or high as its so small/easy to rev up.

i will try to power it off of my big ebike esc with the same 3speed switch and see if there is any difference.

also, yeah hksunwin have already given me a full refund for one of the controllers they sent. both came dropped/dented and the other was totally non functional

its really annoying as i only upgraded the controller to get this number 3 speed (MORE SPEED) and its the only thing that didnt work :s

 

[jimmyhackers]

SOLVED!!

tried out my big ebike 1500w sunwin controller on the little 14" hub wheel

turns out.....high speed doesnt work for this little hub motor or it is so small of an increase its not noticable

i saw a video showing that high speed only added 3% over normal which i wont be able to percieve without an rpm tester.

sorry to waste everyones time, but at least you all know now.

 

[seba240698]

Hi, sorry to ride on this thread the 3-speed switches.

I'm just wondering, what exactly does the controller do when we switch to high speed?

Does it :
1) activate a higher voltage to increase the rpm of the motor? How can it do that, when the MAXIMUM voltage going to the motor is limited by the voltage of the battery?

2) increase the current going to the motor thereby increases the power? But that is power, not top speed, I world think this will increase the acceleration and it hill-climbing ability but not top speed.

So what exactly does the controller do?

Thanks in advance.

 

[E-HP]

Does it :
1) activate a higher voltage to increase the rpm of the motor? How can it do that, when the MAXIMUM voltage going to the motor is limited by the voltage of the battery?

It depends on your controller. If capable, the controller applies field weakening, reducing field strength, which in turn reduces the back EMF. Back EMF is what limits the motor speed. Normally, as motor speed increases, the combination of field strength and motor RPM increases back EMF, which prevents the motor speed from increasing any more. The increase in speed can be as much as 20%.

 

[seba240698]

Wow, that's insightful. I didn't know that back emf can cause as much as 20% speed loss.

Thank you.

 

[E-HP]

Wow, that's insightful. I didn't know that back emf can cause as much as 20% speed loss.

Thank you.

Interesting conclusion, but I didn't say that. It is what limits a motor's speed at a particular voltage. It doesn't cause speed loss.

The top speed of a motor is determined by when the "forward" EMF equals the back EMF. Field weakening adds current in a manner to reduces the back EMF. I barely every use field weakening, since it sucks up more power for a little more speed. Plus, I normally ride my bike at half the speed it's capable of, and FW doesn't do anything until you reach its normal top speed.

 

[jimmyhackers]

i asked the hksunwin manufacturers.

they wouldnt describe the mechanics of voltage and amperage....trade secrets or some nonsense.

all they would say is it limits it to 50% power 75% and 100%.

simply, they said their controller wont give more than the motor can ask for.

they suggested as the wheel i was using is such a small wattage (250w e-unicycle hub motor) that adding a larger controller (1000W +), it wont ask for more power despite the controller being able to provide it.

doing some backwards logic between my two motors, it feasable to say they alter both voltage and amperage between 50% and 75% and just amperage between 75% and 100%.

without getting out an oscillioscope and some proper equipment, or the manfufacturer specifically saying so about their esc.
its hard to really know.

 

[E-HP]

all they would say is it limits it to 50% power 75% and 100%.

Definitely not field weakening or anything special there. Sounds like the trade secret is what they told you, lol.

 

[jimmyhackers]

well yeah, but as power is a function of voltage and amperage.....i asked how they changed the voltage and amperage to get 50% 75% and 100%

apparently that was the "trade secret" :S

is weird though, i only asked them as.....the same 1000w motor on a non hksunwin 1000w ESC that came with the motor kit, only did 40mph at top speed.

hksunwin 1000w or 1500w esc does upto 60mph top speed on same 72v batteries. it made me wonder if my old esc was limiting top speed of wether HKsunwin was doing field weakening or some other thing to get the extra rpm from my motor.