@Joe
Are the coils open to the water or are they in epoxy?
Are the coils open to the water or are they in epoxy?
The OEM controller chip (LM2576) limits at ~6A, so should be ok if we switch off completely after, say, 0.3 sec at >3A, or 0.5 sec at >2A ?I am wondering if 6 amps for the current limit is to much
Not if Joe can just salvage the critical parts. I was thinking perhaps most of the OEM controller pcb could be left as is, with just the odd track snip and a couple of wires brought out to our circuitry, if we knew the OEM layout.We really don't have to do ALL of the controller
For a few mS, yes. Unfortunately rotor lock is likely to last much longerThat LC filter will do some current limiting too.
alec said:Not if Joe can just salvage the critical parts. I was thinking perhaps most of the OEM controller pcb could be left as is, with just the odd track snip and a couple of wires brought out to our circuitry, if we knew the OEM layout.
Do the 68uH/1000uF correspond to the datasheet's 100uH/1000uF switcher filter?
@Joe
Are the coils open to the water or are they in epoxy?
@Joe
Those 6 parts should be in the area of R1, R2 on page 19 of the datasheet. These resistors are 5 band and all end in brown, so the one by T2 is RED-RED-BLK-BRN-BRN. In circuit, I measured 2188 ohms. That value should be 2200 1%, (2188-2222 ohms) The last BRN is 1%; RED, RED, BLK are 3 significant figures and BRN is a multiplier of 1 zero. Not your typical resistor.
Joe, Do you have spice so you can see the schematics?
I hope global warming does't kill all the coral before this gets done.
Tough one:
1. I haven't been able to read the value on the fuse yet. It is a time delay fuse. Fuse is glass, wire leads, 4 x 11 mm. If I were to guess the rating, of the fuse, I'd say between 1 and 3 amps SB. 1.45 A = 35 VA/24 VAC. So a fuse rating of 3A SB would sound about right. Using the resistance of the fuse in circuit, It would be a 0.5 Amp fuse.
2. I initially used a (0-30 VDC) supply rated a 3 amps max. 6A is hard to come by.
3. The OEM AC supply is rated for 35 W, 240 and 240 VAC is hard to come by.
Bet the fuse would blow first. The initial 6A will come from 2000 uF of capacitance. The transformer would start to heat up and drop the voltage. I would even doubt that the regulator would go into thermal protection. 24/2.15ohm > 11 amps. I*R = 6*2.15 = 12.9V
If this is my guess, https://www.electro-tech-online.com/custompdfs/2012/06/673.pdf then at 6A, then a 3A SB fuse is liable to blow in 0.4 s.
I think I saw a 3A on the fuse. Only way to tell is remove and look, but that's what I would size it for. Note that these fuses are I^2*t rated so it would blow in 0.4 s at 6 Amps.
ronv said:Oh, I thought you had the standard supply.
ronv said:The question I was trying to answer was if the standard controller had the same problem as the one Joe built or if it had a different current limit or shut down since we know that 6 amps or worse 11 amps continious is to much.. Could be its supply limits the current to some lower value. Who knows?
I do have the standard supply. A 240 to 120 VAC 25 VA Xformer. That's what comes with it. It isn't for 120V.
Missed that.
The OEM controller rectifies the incoming power, so AC or DC will make it work.
Ok. so we would need a bigger supply to make it work. I get it now. I thought you were using the stock controller.
With 2000 uf of filtering the supply you could sustain 2A, but the power supply is rated to 1.5A so you could only sustain 1.5A.
It has to get the current from somewhere to ever blow the fuse. I suspose the teansformer could drop to 12 volts under a 6 amp load then it would blow in 10 seconds. If its really a 3 amp fuse)
The OEM controller has a 3-6A current limit (regulator), has a fuse which is probably 3A and has a transformer which is rated for 35 VA. The OEM controller is known to have problems (regulator dies) as well. I believe they are: No diodes for back EMF, do diodes to jump the regulator, Poor selection of output caps (not high ripple). This controller has changes to earlier earlier controllers of a fuse and better inductors per pics on the net.
OK
Then there was the solder blob....
That one doesn't susprise me. With the big supply the FET would get hot enough to melt it as well as the coil.
Here is my take on the failure:
The pump FETs have protection from the inductive kick either thru protection in the FET or they are avalance rated for enough current. Without that they would pop in nothing flat.
It could have been a bad part (FET or Hall) but with only 3 active components I would really be suprised that 1 in 100,000 would ever fail in our lifetime.
A mechanical failure - bind in the bearings or pump - this is my favorite.
Perhaps the solder blob moved enough to cause a short. I'll go back and look some more at the pictures.
Maybe being a 2 pole pump it just fails to start sometimes. Again, I think a long shot.
One thing is clear. Both the FET and the coil will fail on the big supply with no current limit and shutdown should it ever stall.
I guess I'm not convinced the stock controller is any better than the Alec supply without knowing more about it.
ronv said:One thing is clear. Both the FET and the coil will fail on the big supply with no current limit and shutdown should it ever stall.
need to clarify said:The OEM controller rectifies the incoming power, so AC or DC will make it work.
ronv said:I guess I'm not convinced the stock controller is any better than the Alec supply without knowing more about it.
ronv said:I wouldn't want to cycle it at .5 seconds on and .5 seconds off that's for sure.
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