Welcome, Guest
Username: Password: Secret Key Remember me

TOPIC: Current Sensing - Best Approach Advice Needed

Current Sensing - Best Approach Advice Needed 4 years 1 month ago #17371

  • hop
  • hop's Avatar
  • Offline
  • Platinum Boarder
  • Posts: 526
  • Thanks received: 46
Jon Chandler wrote:
Even if it's not, adding the diode directly across its terminals is cheap insurance. Given your belt and suspenders and duct tape and staples approach elsewhere, saving a few cents on a diode doesn't make sense.
lol what?
I'm not trying to spare a diode that I have hundreds of, and I'm not crafting this out of a cardboard box and toothpaste either. hehehe

I meant the control circuitry of the motor (a BLDC), which uses a pressure switch as an additional feature along with what I thought was built in to control the coils as in hall effect sensors or rotary encoders, etc.

Current Sensing - Best Approach Advice Needed 4 years 1 month ago #17372

  • Jon Chandler
  • Jon Chandler's Avatar
  • Offline
  • Moderator
  • Posts: 365
  • Thanks received: 352
Ohhhhh....it's a BLDC motor, not a regular DC motor. Sorry, I missed that somewhere along the line.

So the coils in a BLDC motor are switched on & off to make it spin by some control circuitry. Yeah, that is built to handle the back-emf of the coils already. My mistake.

I really wasn't trying to be insulting; the "belt and suspenders and...." Was a poor attempt at humor.

Cardboard, yes. Toothpaste, no...it makes the cardboard soggy. Everyone knows toothpaste is just for hiding nail holes in dorm rooms!
Last Edit: 4 years 1 month ago by Jon Chandler.
The following user(s) said Thank You: hop

Current Sensing - Best Approach Advice Needed 4 years 1 month ago #17374

  • Baldor
  • Baldor's Avatar
  • Offline
  • Expert Boarder
  • Posts: 135
  • Thanks received: 91
First, the image i was trying to post:

Aprendiz de mucho, maestro de casi nada.
Last Edit: 4 years 1 month ago by Baldor.
The following user(s) said Thank You: hop

Current Sensing - Best Approach Advice Needed 4 years 1 month ago #17375

  • Baldor
  • Baldor's Avatar
  • Offline
  • Expert Boarder
  • Posts: 135
  • Thanks received: 91
Now.. BLDC... This is a diferent beast. I think you cant use the aproaches we are discusing here with a BLDC.. .You will have some sort of square wave instead of an ON/OFF signal. I think you should poke around the control circuitry to find a clear ON/OFF signal. Or return to measure current before the black box.
Aprendiz de mucho, maestro de casi nada.
The following user(s) said Thank You: hop

Current Sensing - Best Approach Advice Needed 4 years 1 month ago #17376

  • hop
  • hop's Avatar
  • Offline
  • Platinum Boarder
  • Posts: 526
  • Thanks received: 46
Jon Chandler wrote:
I really wasn't trying to be insulting; the "belt and suspenders and...." Was a poor attempt at humor.
lol, no offense taken my friend.
Jon Chandler wrote:
Cardboard, yes. Toothpaste, no...it makes the cardboard soggy. Everyone knows toothpaste is just for hiding nail holes in dorm rooms!
hahaha that's awesome!

Current Sensing - Best Approach Advice Needed 4 years 1 month ago #17377

  • hop
  • hop's Avatar
  • Offline
  • Platinum Boarder
  • Posts: 526
  • Thanks received: 46
One of the confusing issues with this particular motor is where the control circuitry is. I have to assume it is inside the motor itself since there are clearly two wires going into the back of the motor housing, but the wiring is snaked all around the entire unit. I'll look more closely in a minute.

The hacking point will be where the pressure switch is, and that I believe is encased where the 5/16" ID tube ports are connected. I really do not want to fiddle with that.

So I am open to any suggestions you guys have for monitoring the current drawn that is not invasive.
Time to create page: 0.249 seconds