ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Top Posters(30 Days)
dsk 13
Admin 5
Recent Posts
electircal ageing test on IPC
by SIAME. 08/15/17 02:43 AM
electrical aging test on IPC
by gfretwell. 08/15/17 12:27 AM
Bathroom electrical
by gfretwell. 08/14/17 02:05 AM
"Line level" audio on Cat 5?
by gfretwell. 08/08/17 10:39 PM
Fire alarm phone lines and color coding
by gfretwell. 08/08/17 10:26 PM
New in the Gallery:
Housebilding DIY wiring
Popular Topics(Views)
239,856 Are you busy
175,412 Re: Forum
167,704 Need opinion
Who's Online Now
0 registered members (), 48 guests, and 10 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate This Thread
#54169 - 07/21/05 10:44 AM Contactor  
kinetic  Offline
Member
Joined: Apr 2002
Posts: 156
Phoenix, Arizona
I have a contactor supplied by a plumber for a misting system. It is a Square D 8910DPA. Basically a 3 phase/1 phase contactor with a 24 V coil. It didn't have a wiring diagram and I haven't dealt with contactors before. My question is how do I get the coil to fire? Do I need an external power source?


Work Gear for Electricians and the Trades

#54170 - 07/21/05 01:32 PM Re: Contactor  
Radar  Offline
Member
Joined: Apr 2004
Posts: 349
Los Angeles, CA
Sounds like you need a 24V source to energize the coil, plus some way to control (ON/OFF) the 24V. You also need to confirm the 24V you're talking about is 24VAC as opposed to 24VDC. A 24VAC supply is pretty easy to provide, a 120V circuit feeding a 120V to 24V transformer. The 24V side of the transformer probably needs fuse protection sized to the transformer rating.

Radar


There are 10 types of people. Those who know binary, and those who don't.

#54171 - 07/21/05 03:03 PM Re: Contactor  
earlydean  Offline
Member
Joined: Dec 2003
Posts: 751
Griswold, CT, USA
You could also explore the possibility of swapping the coil out to the voltage you are controlling (208?, 480?). Most contactors will have interchanageable coils of many different voltages.


Earl

#54172 - 07/21/05 03:09 PM Re: Contactor  
earlydean  Offline
Member
Joined: Dec 2003
Posts: 751
Griswold, CT, USA
just checked out the grainger site. There is a 120 volt coil kit you can purchase for $64.


Earl

#54173 - 07/21/05 06:08 PM Re: Contactor  
Rich R  Offline
Member
Joined: Apr 2005
Posts: 27
Florida
Sometimes the controller/timer for the misting system or sprikler system will have a 24 volt output for the pump contactor.

You should find out how they plan on controlling this before spending any money on transformers etc.


#54174 - 07/21/05 11:13 PM Re: Contactor  
kinetic  Offline
Member
Joined: Apr 2002
Posts: 156
Phoenix, Arizona
Thank you for the help. I thought I would need an external power source like you mentioned Radar. I didn't feel like experimenting with the contactor and risk blowing it up or causing bigger problems. The mister is 240V 1 phase and I was going to ask the plumber to get a different contactor with a 240V coil but he left town for vacation this week. Easier for me to get a simple multi-tap transformer and be done with it. The other misting systems I helped install all had internal controllers but for some reason this one did not.


#54175 - 07/21/05 11:16 PM Re: Contactor  
renosteinke  Offline
Cat Servant
Member
Joined: Jan 2005
Posts: 5,316
Blue Collar Country
One of my favorite new "Candid Camera" episodes showed what happened when they connected the misters at a supermarket produce case to a motion sensor. Customer approached produce, mister fired...:-)


#54176 - 07/22/05 11:03 AM Re: Contactor  
kinetic  Offline
Member
Joined: Apr 2002
Posts: 156
Phoenix, Arizona
Hmmmmmm.....you trying to give me ideas? This guy has a pretty good sense of humor. He might actually like that.


#54177 - 07/22/05 11:23 AM Re: Contactor  
Alan Belson  Offline
Member
Joined: Mar 2005
Posts: 1,803
Mayenne N. France
The contactor needs to have the single phase Hot 'snaked' through the contacts to equalise the overload 'heaters' if fitted- see my question posed 04 26 2005 under 'Motor Starter' ( currently on p. 9 ) for the good advise I got. Will a 240-24V transformer, plus casing, be cheaper than a new 240v coil?
Alan


Wood work but can't!


Member Spotlight
TOOL_5150
TOOL_5150
Bay Area
Posts: 61
Joined: August 2007
Show All Member Profiles 
Featured:

2017 Master Electrician Exam Preparation Combos
2017 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Shout Box
Powered by UBB.threads™ PHP Forum Software 7.6.0
Page Time: 0.014s Queries: 14 (0.003s) Memory: 0.8008 MB (Peak: 0.9712 MB) Zlib enabled. Server Time: 2017-08-16 15:31:54 UTC