Discussion in 'Electrical & Radio' started by Litch42f, Apr 3, 2019.
Good to know. I looked At my pump last night. It has the same issue
Just wanted to follow up I moved my pump discharge. It is now located at the top of the pump casing. I did a few test and the pump was a BEAST. No priming issues at all! To bad that the new BC pump can not be modified like the old school one. I’m on the look out for old school BC pumps if there are any available for purchase
When you have a 3d printer, lots of things are suddenly options... like building an entirely new body&volute around the BC impeller...
I really need to revisit this project. Right now it needs a bit too much hand-work after printing for my likes, and I want to move the priming hole (I basically kept the BC location, but i'm not a big fan of it there)
The picture isn't working for me...
Did you get .step files for the BC pump, or did you just design based off the small engineering drawing on the BC site? I like your vertical output, wish BC would offer that as an option.
bought a pump. didn't like the body and wanted to mount up a brushless motor. Was originally going to just remodel the top-plate for the brushless mount but since I didn't like the rest of the body I just took a few measurements off things and set about making something around the impeller. I've never really liked printing impellers.
D'oh. That makes too much sense haha. Who would've thought, taking physical measurements!
With all due respect to the bc style pumps. They will be prone to priming issues until a volute is added to the water path. What you're missing is time and space for the energy to be converted from kinetic to pressure. My experience is with hydraulics and turbos but fluid dynamics are more or less the same.
A spiral. The tighter you make it the worse the effect will become.
PS EDIT- looks like the volute is being incorporated in the latest 3d-print designs. Well done fellows.
Indeed there is a lot that can go right or wrong in the volute.... A lot of efficiency loss can occur there. you can also split the volute if you wish to reduce the radial side load from pressure on the impeller and it's bearings. I have had good success with split volutes.
Yes. In each instance except for the newest 3d-print above the impellers have been mounted central in the pump housing. This "stalls" the blades and causes more flow turbulence the tighter is becomes. The flow needs time and a direction to accelerate.
Lots can go wrong but less if the fundamentals are adhered to. A volute is defined as an ever increasing spiral. It's the part that makes it a pump.
This video is pretty good for design inspiration.
Wow, over a year since the last post in this thread, where does the time go? I wanted to try and keep bilge pump content in one thread so I’m semi-reviving this one. So I’ve been messing around with brushless pump motors recently and have been using the hobbyking prop drive series out runner motors. They seem to work reasonably well. That being said I’ve had two of them fail after only a few battles. In one case the motor would rotate slowly and erratically and heat up the ESC and associated wires significantly. The other time the motor seemed to just stop responding completely and fried my ESC. Both instances involved a sink so I’m wondering what everyone does as far as post battle maintenance on their brushless motors?
I only have about 1 full season of pond time with them (4x weekend events and 1x nationals), here's what I do each evening after a day of battle. So far no failures, I had one bearing going bad but preemptively replaced prior to mid-battle failure
Remove pump from boat
Dunk the pump in alcohol, rotate the motor (ideally submerge motor). I do this so the alcohol will cause water to evaporate away
Lubricate upper and lower motor bearings (I use Fluid Film) - rotate the motor to distribute
For lower bearing, I drill hole through motor plate so I can shoot the fluid film into the cavity between the lower motor bearing and impeller
place pump in front of fan to help dry out
For your situation I would try to further diagnose the failure mechanism (i.e. is it bearings, magnet delaminate, poor ESC or waterproofing, etc). I also don't run my pump when submerged although I don't have data if that leads to failures or not
Here's my video of pumps which I think discusses some of the above
I don't have a brushless pump, but I do use brushless drive. slow and erratic motion sounds like a single-phase failure, although whether that's a failure of the ESC or motor I cannot say. The other one sounds like possibly debris or seized bearings? I have learned to be very protective of my brushless motors, I carefully run each motor for several minutes and oil every bearing as soon as the battle day is over. Maintenance takes around 45 minutes to an hour at the hotel, but a fair amount of that is spent pulling apart my tetris-stack predreadnought (it's a very tight fit, only goes together one way) and disassembling the pump so I can access the lower bearing. I like Kevin's idea to drill an access hole for the lower bearing, that sounds like a great way to save time on disassembly.
I spray down mine with a dry film lube before they ever get wet and then hose them off periodically with oil or dry film lube. that seems to do a pretty good job of getting the water out. After battle is over I blow them out with compressed air and put a fan on them to dry. All bearings are accessible from the outside with oil in pumps I use.