ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Shout Box
Recent Posts
Linear Power Supply Quits Under Load
by JoeTestingEngr. 10/18/18 08:47 PM
220/230/240V 60Hz Systems
by dsk. 10/17/18 01:25 PM
PLC/HMI Enclosure C2, D1
by ghost307. 10/16/18 03:31 PM
Tingle off the water spigot
by dsk. 10/15/18 02:36 PM
New in the Gallery:
What is this for?
Plug terminals
Who's Online Now
0 registered members (), 20 guests, and 25 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
Load control in generator start up #213964
09/14/14 10:33 PM
09/14/14 10:33 PM
ChrisCrawford  Offline OP
New Member
Joined: Sep 2014
Posts: 2
Molokai Hawaii USA
We installed 5 new Daikin A/C units on a large house with a back up generator and there are problems with the low voltage at generator start up messing with the A/C units (blowing fuses, etc.) Any recommendations on how to delay the power up of A/C units to after the generator stabilizes such as a time delay power relay that we could install that is available? Thanks


Chris Crawford, Space Options, Molokai Hawaii
Work Gear for Electricians and the Trades
Re: Load control in generator start up [Re: ChrisCrawford] #213966
09/15/14 01:27 AM
09/15/14 01:27 AM
J
JoeTestingEngr  Offline
Member
Joined: Nov 2005
Posts: 799
Chicago, Il.
I would think it best to make sure any ATS doesn't switch until the emergency source is within frequency and voltage tolerances. Then, if I had problems with multiple compressors trying to start at the same time, I would consider TDOs on the control voltages. By time delay switching power to the control ckts, the units would just "wake up" at different times after a power outage. All high currents would be switched as they always are. This would also help on return to the normal source, and if set long enough, help prevent short cycling of the compressor(s).
Joe

Re: Load control in generator start up [Re: ChrisCrawford] #213967
09/15/14 02:56 AM
09/15/14 02:56 AM
G
gfretwell  Online Content

Member
Joined: Jul 2004
Posts: 9,298
Estero,Fl,usa
Most HVACs have a time delay module in them from the factory these days but they are a delay after power off deal. If the power was off for X minutes it starts immediately.
For the OP's problem you want "delay on" relays set to different times for each compressor.
Five to Ten seconds between starts should do the trick without being that noticeable to the users.

http://www.grainger.com/category/time-delay-relays/relays/electrical/ecatalog/N-8erZ1z0move


Greg Fretwell

Featured:

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

 

Member Spotlight
Attic Rat
Attic Rat
Bergen Co.,N.J. USA
Posts: 524
Joined: December 2003
Show All Member Profiles 
Top Posters(30 Days)
sparky 11
Popular Topics(Views)
250,620 Are you busy
188,123 Re: Forum
177,800 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.6.1
(Release build 20180101)
Page Time: 0.023s Queries: 15 (0.006s) Memory: 0.9526 MB (Peak: 1.0788 MB) Zlib enabled. Server Time: 2018-10-22 16:32:20 UTC