Use PWM to control your Jebao DCT pump using brushless motor controller from ebay

[karimwassef]

If it's generating less power drive, is it a frequency mismatch maybe? Then a fix could be changing a timing resistor/cap?

What are the other control variables?

The FETs can handle it, so... there's got to be a path forward.

[d0ughb0y]

the board I got is marked JYQD_V6.3E1
and I can't find any other version for this board.
I know there is a version of this board for motors with hall sensors and that won't work with the jebao pumps. The LM339 chip is missing from the board.

The board is advertised as used in electric scooters and bikes.

The speed is proportional to voltage/pwm. I checked the commutation signal with pwm connected to 5v, and I still see pwm like signal. I think that is reducing the output voltage. I'll check the BEMF circuit, maybe later this week, to see if I can find anything.

[d0ughb0y]

The standard driver circuit, as per datasheet looks like this



I found an article with a slightly modified circuit (but using IR2110).



It should not be hard to solder a 1k resistor between the Gate and Source of all 6 MOSFETS. Adding the diode might be a little bit trickier as you need to solder to SOP-8 smd pin. I will try adding the 1k resistor. I won't be able to do it till later this week.

[karimwassef]

Originally Posted by d0ughb0y

the board I got is marked JYQD_V6.3E1
and I can't find any other version for this board.
I know there is a version of this board for motors with hall sensors and that won't work with the jebao pumps. The LM339 chip is missing from the board.

The board is advertised as used in electric scooters and bikes.

The speed is proportional to voltage/pwm. I checked the commutation signal with pwm connected to 5v, and I still see pwm like signal. I think that is reducing the output voltage. I'll check the BEMF circuit, maybe later this week, to see if I can find anything.

Mine has the same marking

[karimwassef]

I wanted to document the Apex connections and clean up the overall design outside the board



with color coding to make it easier for others to do the same.

My VDM was outputting 0-10.8VDC so I needed to modify the resistor divider network to get exactly 0-5VDC (as close as I could). I checked it with two different multimeters and it's real.

Here is the resulting APEX programmed input (0-100) and measured VDC



Here are some pics of the connections

[karimwassef]

Originally Posted by d0ughb0y

The standard driver circuit, as per datasheet looks like this



I found an article with a slightly modified circuit (but using IR2110).



It should not be hard to solder a 1k resistor between the Gate and Source of all 6 MOSFETS. Adding the diode might be a little bit trickier as you need to solder to SOP-8 smd pin. I will try adding the 1k resistor. I won't be able to do it till later this week.

Is the idea that the 1K will improve the commutation timing to get more throughput power?

[karimwassef]

I think I'll add a small wire connection to the gate first and then wire the 1K to that.

Eh - it's a $12 board and there's two more on the way. If it doesn't work, at least we'll know.

[karimwassef]

Here's a closer look at the Ethernet resistor network



If I could go back, I'd get a 1K-10K pot instead of measuring and stringing resistors.

[d0ughb0y]

Originally Posted by karimwassef

I think I'll add a small wire connection to the gate first and then wire the 1K to that.

Eh - it's a $12 board and there's two more on the way. If it doesn't work, at least we'll know.

All you need to do is solder 1k to pins 1 and 3 of each MOSFET. You can do it either on top side or bottom side. The resistor is to prevent surge current. The diode is for faster discharge of the FET capacitance, or something like that. In the above circuit, the mosfet gate resistor is 10 ohms, the one on the green board is 510ohms. Perhaps the value may be too high, so I think the diode could make a difference.

I think that's about all you can do with the driver circuit.

I have to check the back emf feedback circuit.

[karimwassef]

ok. based on the datasheet:

http://www.maxim4u.com/download.php?...90_8192231.pdf

I'm going to connect gate to source with 1K:



right?

[karimwassef]

Originally Posted by karimwassef

Here's a closer look at the Ethernet resistor network



If I could go back, I'd get a 1K-10K pot instead of measuring and stringing resistors.

The image got corrupted. Here it is again:

[karimwassef]

would this controller not work without the hall sensors?

http://www.ebay.com/itm/NEWEST-DC-12...d/231954428640

or just go beefier?

http://www.ebay.com/itm/12V-24v-30A-...-/111954645718

[stage3-s4]

I'm in the process of setting up a flow meter to measure flow. Just waiting on my signal converter to come in. Once I have that, I can test flow rates fairly easily.

[d0ughb0y]

Originally Posted by karimwassef

would this controller not work without the hall sensors?

http://www.ebay.com/itm/NEWEST-DC-12...d/231954428640

or just go beefier?

http://www.ebay.com/itm/12V-24v-30A-...-/111954645718

The first one requires hall sensor, so it won't work with jebao pump.

the second one is rated 18v max only.

I'm thinking another thing to try is to replace the mosfet. The specs of the mosfet used on the board looks fine, but maybe the quality may not be good.

I am also going to capture the 6 motor drive signals for the green board and compare it to the data I captured from the stock controller just to make sure the phase is similar.

I think it is just a matter of component value choice to get this working.

regarding the addition of the diode to help discharge FET capacitance. I just check the specs again, and the input capacitance of the NE6990 is 2 to 3 times higher than a couple other MOSFETs I checked. So perhaps either adding the diode or changing the mosfet may improve the power.

[karimwassef]

Originally Posted by karimwassef

ok. based on the datasheet:

http://www.maxim4u.com/download.php?...90_8192231.pdf

I'm going to connect gate to source with 1K:



right?

Here's the missing image

[karimwassef]

Originally Posted by stage3-s4

I'm in the process of setting up a flow meter to measure flow. Just waiting on my signal converter to come in. Once I have that, I can test flow rates fairly easily.

Which flow meter? Where did you get it from?

[stage3-s4]

https://www.amazon.com/DIGITEN-Effec...rds=flow+meter

People claim that this G thread or BSP thread wouldn't work with NPT fittings. That was my only concern, but I got it over the weekend and it fits perfectly with a 1" female NPT fitting. Put some teflon tape on it and it will seal just fine.

Anyway, its just a simple hall effect senor that outputs a PWM singal. I need the signal conditioner to converter it to a 4-20mA signal to input into my PLC.

[stage3-s4]

Originally Posted by d0ughb0y

The first one requires hall sensor, so it won't work with jebao pump.

the second one is rated 18v max only.

I'm thinking another thing to try is to replace the mosfet. The specs of the mosfet used on the board looks fine, but maybe the quality may not be good.

I am also going to capture the 6 motor drive signals for the green board and compare it to the data I captured from the stock controller just to make sure the phase is similar.

I think it is just a matter of component value choice to get this working.

regarding the addition of the diode to help discharge FET capacitance. I just check the specs again, and the input capacitance of the NE6990 is 2 to 3 times higher than a couple other MOSFETs I checked. So perhaps either adding the diode or changing the mosfet may improve the power.

I'm with you on this. I think it may just be that the components used are not the best quality. I have found this to be the case on lots of electronic parts coming in from china.

[d0ughb0y]

Originally Posted by stage3-s4

https://www.amazon.com/DIGITEN-Effec...rds=flow+meter

People claim that this G thread or BSP thread wouldn't work with NPT fittings. That was my only concern, but I got it over the weekend and it fits perfectly with a 1" female NPT fitting. Put some teflon tape on it and it will seal just fine.

Anyway, its just a simple hall effect senor that outputs a PWM singal. I need the signal conditioner to converter it to a 4-20mA signal to input into my PLC.

I take it this does not have any metal part in contact with water right? This would be a nice addition to a controller.

[stage3-s4]

Originally Posted by d0ughb0y

I take it this does not have any metal part in contact with water right? This would be a nice addition to a controller.

Its pretty much all plastic. I haven't taken apart the entire thing yet to verify. The shaft for the wheel inside could be stainless steal but its so small I'm not worried about it. You could easily add something like this to your controller. I think its great to have with a variable pump. You could start to program PID control loops and stuff if you really wanted to get crazy.

I went to Reefapaloza this weekend and of course neptune was there displaying the new flow meter that they are coming out with. Its almost identical to this one. I asked when I could buy one and no one could confirm a date or price yet. Why wait for theirs?

[karimwassef]

Ok. I got the 2" version. I'll need to get my arduino to count pulses. The flow of the 1" is too low. The max for the 2" is 2700gph and that's close to what the DCT15000 runs at

[karimwassef]

Originally Posted by d0ughb0y

I take it this does not have any metal part in contact with water right? This would be a nice addition to a controller.

Yup!! Going to experiment. I'm thinking this is key for critical loops like main circulation and then maybe to capture flow in test setups (like testing my surge!).

[stage3-s4]

Originally Posted by karimwassef

Ok. I got the 2" version. I'll need to get my arduino to count pulses. The flow of the 1" is too low. The max for the 2" is 2700gph and that's close to what the DCT15000 runs at

Yea I figured the 1" may not flow enough. I'm never going to need more than 900GPH on my 40 gallon tank so the 1" was fine. This thing will deff have a pretty significant pressure drop though. It seems very restrictive.

They also make a digital display if you just want to use it to read flow rates directly without a controller.

[d0ughb0y]

I can see why the flow can be restrictive.
I found this picture of what the inside looks like. Looks like it has a metal shaft.



At higher flow rate, it might be negligible, but I imagine this will be another thing you have to take out and clean periodically. I don't know if it is feasible to use this permanently installed. Maybe it is, only time will tell.

I just cleaned my return pump yesterday (so I can figure how to replace the ehiem pump with the jebao pump) and the valve above the union is completely stuck, and when I put my finger to see why, it feels like a lot of calcium build up. So the flow meter might get that as well over time, and may need to be removed for a vinegar bath. If you are able to read the flow, then you will probably know when its time to clean it. And you are right the stainless steel shaft should be fine. The MJ pumps have been used in saltwater for a long time and these have steel shafts. I think my MJ pump has been in saltwater for over 5 years now.

[karimwassef]

Looks like a typical powerhead cleaning job. They all have SS shafts. Just need two unions and a standby fitting that's the same length during maintenance

I may not put it on my main flow, but on the aux I keep in place in case the two primary pumps fail.

I have three DCT15000s. I prefer to buy cheap and add in redundancy. So, even if one pump fails while I'm traveling, the likelihood of all flow stopping is minimal. Same with pH probes, surge loop actuators, etc...

I still have a few single points of failure but I'm slowly adding massive redundancy where I can.

Still haven't figured out how to do that with my Apex. I have two of them, but I have to physically disconnect and reconnect the other in case of failure... Redundancy is the only path to cost effective quality and uptime IMO

but that's probably an aside for your other thread.