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Old 03-30-2012, 12:43 PM   #21
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As pointed out, that's a 3-phase (see 3 large connections to the windings) permanent magnet (PM) brushless DC (BLDC) motor. It's "DC" because a circuit, an inverter, with 6 MOSFETs, converts DC to 3-phase AC. The inverter uses a position (hall-effect) sensor to sense the position of the rotor (which has permanent magnets) and flips the phase of the AC at the right times (right position) of the rotor to generate torque.

Fun fact, an alternator is the inverse of a BLDC motor if you replace the rotor's "electromagnets" with a bunch of permanent magnets.

Many BLDC motors (such as computer fans) just take power and ground and simply turn the load as fast as it will go which will be a function of how much voltage you apply.

As pointed out as well, this particular fan's board may take a DC or a digital comm signal to tell the inverter how fast to turn the motor.

The above schematic suggests that pin 3 accepts a pulldown signal, perhaps DC, PWM, or a comm signal. PWM is probably the most likely. You may be able to find the pump's datasheet or application notes somewhere.

Here's a tip when testing random signal input pins - do not directly connect them to 12V or gnd. Connect them via a 100 or 1k resistor. The resistor will limit the current and prevent possible damage. Having said that, automotive electronics are protected against connections to 12V and to gnd... Also if you have a bench power supply with a **** to adjust max current, set it as low as possible and only turn it up slightly as needed.

Lastly to check your pump, measure the current that it takes into the 12V. It should probably between a fraction of a mA to a few mA, if the pump doesn't run. If it's zero one of the fuses is blown (the little yellow things in the photo of the guts)

Last edited by JasonC SBB; 03-30-2012 at 03:28 PM.
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Old 03-30-2012, 02:37 PM   #22
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T-tim,

In the 'guts' pic:
I'm betting the li'l silver 'E's and 'forks' at 6 o'clock are (were) fuses.
I'd also gander a guess that the part with the qr code on it is a controller, or maybe a package of fets. Idk.
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Old 03-30-2012, 04:23 PM   #23
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Quote:
Originally Posted by RattleTrap View Post
I'm betting the li'l silver 'E's and 'forks' at 6 o'clock are (were) fuses.
I'm pretty sure that they're just connecting wires to join things that shouldn't move (the circuit board) to things that might move a little bit (the various external contacts). That sort of fusion-bonding is a pretty cheap and simple process to automate as an alternative to soldering. Crack open the VAF sensor on a 1.6 Miata and you'll see something vaguely similar.



Random thought: what does the mechanical interface between the motor and the impeller look like? I'm wondering if you could easily transplant a conventional DC motor (such as are used by ShurFlo, et al) onto the pump housing.
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Old 03-30-2012, 11:56 PM   #24
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Quote:
Originally Posted by Joe Perez View Post
I'm pretty sure that they're just connecting wires to join things that shouldn't move (the circuit board) to things that might move a little bit (the various external contacts). That sort of fusion-bonding is a pretty cheap and simple process to automate as an alternative to soldering. Crack open the VAF sensor on a 1.6 Miata and you'll see something vaguely similar.



Random thought: what does the mechanical interface between the motor and the impeller look like? I'm wondering if you could easily transplant a conventional DC motor (such as are used by ShurFlo, et al) onto the pump housing.
Thanks everyone for the help and description of how this thing works. It's all coming back to me now.

Next will be to disassemble the impeller housing from the main body & see how that's all held together. I can see that the shaft is hollow and that the back side seal cup thing is pressurized. It's kinda trick in a "way too complicated than it needs to be" sorta way. Just like the motor control. I'll price out a typical 2 wire DC motor. Again, cheapest is the mech. pump already on there....there's nothing wrong with it. This pump was sitting around and I was given the go-ahead to see if it would work.

I get a blip of current on the powersupply display briefly when I connect to Pin 1. I haven't been using a resistor while trying all of this...oops!
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Old 03-31-2012, 01:34 AM   #25
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I get a blip of current on the powersupply display briefly when I connect to Pin 1. I haven't been using a resistor while trying all of this...oops!
That's the big capacitor charging.
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Old 04-03-2012, 05:35 PM   #26
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OK got it to work. Pierburg clued me in to the actual Pin assignments, 1 is supply voltage, 2 is PWM input, 3 you don't have to worry about. So after hooking 1 & 2 to +12v and waiting about 5 seconds, it turns on. It's the whole waiting thing that I didn't try. This spins at 3500rpm when pin 2 is set to 100duty cycle.

The PWM input does slow it down (after that ~5sec lag) and there is a wide range of PWM frequencies that will work. I wasn't operating the frequency generator but the lab guy said he was trying a bunch and it all worked. I can find out a definite frequency that works.

Is there anyone who can make me a tuneable PWM circuit that uses a coolant temp sensor as an input and allows me to control/tune the coolant/duty cycle curve? Otherwise I may wire it 100% and use a thermostat, but according to the info from Pierburg, this is a 30gal/min pump at full tilt.

Or possibly a circuit that isn't closed loop...perhaps a potentiometer that controls duty cycle that I set at whatever, and I can use the AEM to trigger a relay to 100% at whatever coolant temp, perhaps a few degrees before the cooling fans turning on.

+12vdc square wave.

Thoughts?
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Old 04-03-2012, 05:55 PM   #27
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Easy peasy.

Give me the desired temp range, e.g. first turns on at 90*C, full power at 100*C.

Then the voltages at the thermosensor at the above min and max temps.

Do you want it in an Arduino or in an analog circuit?


BTW if you control speed with temperature, you will need a separate small pump for the heater circuit. And the thermosensor should be bathed in the coolant that is about to leave the head to enter the heater.

I would put this sucker in the upper rad hose, to reverse flow the coolant (coolest coolant into head first). Reduces detonation.
And use Evans NPG+ coolant - will prevent steam pockets that reverse flow is more prone to, (IIRC).

How much is that sucker anyway?
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Old 04-03-2012, 07:25 PM   #28
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Jason,

Thanks for your help! I am not sure the difference between Adruino and analog. I will search that out. This is still a month or two away to needing this.

I was thinking about that heater circuit just now, and whether or not to use a thermostat. I guess one of the main reasons for the circuit is to delete the thermostat...then yeah, the entire coolant has to heat up along with the engine as the pump spins slowly and the heater will not work as well. I think the pump should always spin at say 30% duty then increase as temps rise. THis may be a PITA. So keeping a thermostat in there may be better & simplier to debug. The heater would work, the engine should heat up quicker (important as the cylinders were incorrectly bored on the large side and they are 2618) and the thermostat will help control temp as well. I could also then run the pump wide open if needed. Have heater core return between radiator and pump.

I was also staring at the engine when I got home, reverse flow looks simple to do. Both coolant in/outs are right next to each other

EDIT: VP looked up the invoice for the pump, retail was ~$550 remanufactured, from BMW. I have seen them online for much less however.
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Old 04-03-2012, 08:08 PM   #29
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DDDuuuudde this Arduino thing looks pretty cool. Only ~$25 from amazon too, plus some sort of case. I have to see if it can output PWM at 12 volts instead of 5 I'm reading thru some of the sample codes and I haven't seen where you control frequency yet. But that looks simple to program the 'curve' as needed though!
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Old 04-03-2012, 09:01 PM   #30
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Turning a 5V PWM signal into a 12V pulldown is cake.
Just use something like this, with a 1k gate resistor.
http://search.digikey.com/us/en/prod...0-5-ND/1039352
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Old 04-03-2012, 09:05 PM   #31
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Quote:
Originally Posted by TurboTim View Post
Jason,

I was thinking about that heater circuit just now, and whether or not to use a thermostat. I guess one of the main reasons for the circuit is to delete the thermostat...then yeah, the entire coolant has to heat up along with the engine as the pump spins slowly and the heater will not work as well. I think the pump should always spin at say 30% duty then increase as temps rise.
Negatory. If you spin at 30% duty and pump coolant through the radiator slowly, the engine will take forever to warm up.

Quote:
THis may be a PITA. So keeping a thermostat in there may be better & simpler to debug.
Inserting a t-stat will defeat one of the advantages of having an electric pump - reduced load.

Why not use a small pump to pump through the heater until the main pump turns on?

If you insist on a t-stat, then route the heater as a bypass, and set up the logic so that the pump is forced to run at some minimum speed only when the heater blower is turned on and the engine is cold.

BTW do you know how much current the pump draws flat out?
If you're gonna measure it, make it pump water out of a bucket. See also how high it can shoot the water up vertically, to give an idea of how much head pressure it can deliver.

Quote:
EDIT: VP looked up the invoice for the pump, retail was ~$550 remanufactured, from BMW. I have seen them online for much less however.
Nothing made by the 3rd party OEM / ODM manufs on rockauto?
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Old 04-03-2012, 09:20 PM   #32
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Not sure how to use that gizmo to convert 5vdc to 12. Not so simple to an electrical idiot such as me.

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Negatory. If you spin at 30% duty and pump coolant through the radiator slowly, the engine will take forever to warm up.

Inserting a t-stat will defeat one of the advantages of having an electric pump - reduced load.

Why not use a small pump to pump through the heater until the main pump turns on?
Adds cost, hoses, complexity, points of failure, takes up room, etc. I'm trying to keep it cheap and simple. I am only looking at this pump because it's free and I may be able to use the extra space front&center for big turboz.

Quote:
If you insist on a t-stat, then route the heater as a bypass, and set up the logic so that the pump is forced to run at some minimum speed only when the heater blower is turned on and the engine is cold.
not sure I see the logic behind running it at a min speed only when heater fan is on. To me it makes more logic to run it at min speed based on cold engine coolant temp regardless if the heater blower is on or not.
Quote:
BTW do you know how much current the pump draws flat out?
If you're gonna measure it, make it pump water out of a bucket of water.
I do not know current draw and me setting up the stuffs to measure that is unlikely.

EDIT: I will be using a 100amp alternator.

Quote:
Nothing made by the 3rd party OEM / ODM manufs on rockauto?
I haven't searched.
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