I'm not talking about stop, I'm talking about running them too slow. My stop is set super fast , and works great. Cranking motor speed down too far, and amp draw goes way up, and VFD gets unhappy.Desert Diver wrote:Jeff, I never noticed this thread had continued till right now. The reason the VFD shuts down when you slow a motor too quickly is because when you reduce the frequency the motor is generating back onto the DC buss of the VFD and most VFD's have no way to put that power back to the incoming line. When the DC bus voltage goes too high the VFD shuts down to protect itself. Most VFD's have a place to hook up resistors so the waste power from slowing down the motor can be shunted to the resistor bank. I have this setup on my small lathe, and have put them on sawmill VFD's. I can set the deceleration time on my small lathe to 1/2 second and it stops like you hit it in the head. In one of the sawmill applications a log running at speed in the same direction as the chipping heads and saws cutting on it could be braked rapidly any time the heads or saws started to go overcurrent. I put overcurrent sensors to protect the resistor banks but have never tripped them and the motors seem to deal with it very well.Jeff Pack wrote:Only downside, is when you slow'm down too much , heat builds up in the motor, and the VFD will shut it down.
Brian
Craigslist deals
Re: Craigslist deals
=============================================
- I got a good squirt in my mouth
- I would imagine that there would be a large amount of involuntary gagging
- I don't know about you but I'm not into swallowing it
CCR discussion on Caustic Cocktails.
- I got a good squirt in my mouth
- I would imagine that there would be a large amount of involuntary gagging
- I don't know about you but I'm not into swallowing it
CCR discussion on Caustic Cocktails.
- Desert Diver
- Extreme Diving Machine
- Posts: 472
- Joined: Tue May 22, 2012 9:20 pm
Re: Craigslist deals
True story. If you have a load that decreases with speed you can get away with 10-15hz but VFD's are not really replacements for gearboxes. They work best set up to run things overspeed. I have run 1800 rpm gearmotors at 5400 rpm for a particular purpose and you get better motor cooling and lower amperage so long as load doesn't go too high with the additional speed. For really low speed running you can put external fans on the motor and adjust the volts/hertz curve to match the motor better.
Re: Craigslist deals
=============================================
- I got a good squirt in my mouth
- I would imagine that there would be a large amount of involuntary gagging
- I don't know about you but I'm not into swallowing it
CCR discussion on Caustic Cocktails.
- I got a good squirt in my mouth
- I would imagine that there would be a large amount of involuntary gagging
- I don't know about you but I'm not into swallowing it
CCR discussion on Caustic Cocktails.
Re: Craigslist deals
"Just to be clear, doing the Diamond Knot requires at the minimum double IPAs to be DIR." - MattleyCrue
"Mmmm....... Oreos!
They didn't look too good when I was spitting in my mask for dive #2!" - cardiver
"Mmmm....... Oreos!
They didn't look too good when I was spitting in my mask for dive #2!" - cardiver
Re: Craigslist deals
=============================================
- I got a good squirt in my mouth
- I would imagine that there would be a large amount of involuntary gagging
- I don't know about you but I'm not into swallowing it
CCR discussion on Caustic Cocktails.
- I got a good squirt in my mouth
- I would imagine that there would be a large amount of involuntary gagging
- I don't know about you but I'm not into swallowing it
CCR discussion on Caustic Cocktails.
Re: Craigslist deals
Saw this on CL, these are great lights, I have a set that I use all the time...
http://seattle.craigslist.org/skc/pho/4792540587.html
http://seattle.craigslist.org/skc/pho/4792540587.html
----
"I survived the Brittandrea Dorikulla, where's my T-shirt!"
"I survived the Brittandrea Dorikulla, where's my T-shirt!"
Re: Craigslist deals
Any one looking for XXL OMS fins (I love mine)
http://seattle.craigslist.org/see/spo/4816748028.html
http://seattle.craigslist.org/see/spo/4816748028.html
The ocean is a lousy teacher. First you get a test, then the lesson.
- finnegankp
- Dive-aholic
- Posts: 293
- Joined: Fri Sep 10, 2010 11:26 am
Re: Craigslist deals
http://seattle.craigslist.org/est/spo/4913953535.html
Oceanic Excursion BCD - Well Maintained w/warranty $350 obo
Oceanic Excursion BCD - Well Maintained w/warranty $350 obo
To dive? Or not to dive?... the latter is irrelevant! Get in the water!
Re: Craigslist deals
http://seattle.craigslist.org/sno/spo/4931828566.html
Selling a bunch of extra/unused gear that's been sitting around for too long...
Manifold, argon straps, bands, SMB, lift bag, strobe, cave reel, camera, Dive Alert, plus misc extras
Selling a bunch of extra/unused gear that's been sitting around for too long...
Manifold, argon straps, bands, SMB, lift bag, strobe, cave reel, camera, Dive Alert, plus misc extras
Re: Craigslist deals
http://seattle.craigslist.org/see/spo/4985787579.html
2 - Faber steel LP80's (+ rated, 2014 hyrdo)
2 - Faber steel LP 95
I messaged with the seller this morning - great guy and willing to answer questions.
2 - Faber steel LP80's (+ rated, 2014 hyrdo)
2 - Faber steel LP 95
I messaged with the seller this morning - great guy and willing to answer questions.
Craigslist deals LOT OF TECH GEAR
Looks like a pretty decent hit, and for 3500 it might be worth it
http://seattle.craigslist.org/tac/for/4973745166.html
http://seattle.craigslist.org/tac/for/4973745166.html
**Pinch it, don't stick your finger through. You're just pinching a bigger hole.
CAPTNJACK - 2012**
CAPTNJACK - 2012**
Re: Craigslist deals
**Pinch it, don't stick your finger through. You're just pinching a bigger hole.
CAPTNJACK - 2012**
CAPTNJACK - 2012**
Re: Craigslist deals
Wow.. that's a great price for 119'sGdog wrote:119 Din tanks....
https://seattle.craigslist.org/est/spo/5062157060.html
The ocean is a lousy teacher. First you get a test, then the lesson.
Re: Craigslist deals
Anyone need a Scooby?
Re: Craigslist deals
just bought 2, thanks Mike
Re: Craigslist deals
$20000 for a turn-key dive training operation (a trailer with all the goodies). Not sure if this is a good deal, just thought it was kind of amazing.
http://denver.craigslist.org/bfs/5232636926.html
http://denver.craigslist.org/bfs/5232636926.html
Re: Craigslist deals
Wow... That is actually quite impressive. In spite of the crappy oceanic tropical bcds. Well organized and thought out.
-
- Frequent Bubbler
- Posts: 27
- Joined: Thu Feb 23, 2012 10:07 pm
Re: Craigslist deals
http://seattle.craigslist.org/tac/spo/5336010661.html
http://seattle.craigslist.org/tac/spo/5335871810.html
http://seattle.craigslist.org/tac/spo/5334812317.html
motivated to sell!
http://seattle.craigslist.org/tac/spo/5335871810.html
http://seattle.craigslist.org/tac/spo/5334812317.html
motivated to sell!
Life is good, let's dive!!