ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Top Posters(30 Days)
twh 10
Admin 4
Recent Posts
Windows 10, who's upgraded?
by ElectricianBud. 05/27/17 11:02 AM
How do you find a good employee?
by ElectricianBud. 05/27/17 10:58 AM
Recall notice: Bosch Solar panels
by ElectricianBud. 05/27/17 10:53 AM
Correct rotation, wrong sequence
by Potseal. 05/27/17 12:15 AM
Dryer, Range grounding from "Main" panel
by sparkync. 05/25/17 05:49 PM
New in the Gallery:
SE cable question
Popular Topics(Views)
236,902 Are you busy
171,910 Re: Forum
164,800 Need opinion
Who's Online Now
1 registered members (richard), 64 guests, and 9 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate This Thread
#213964 - 09/14/14 10:33 PM Load control in generator start up  
ChrisCrawford  Offline
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

#213966 - 09/15/14 01:27 AM Re: Load control in generator start up [Re: ChrisCrawford]  
JoeTestingEngr  Offline
Member
Joined: Nov 2005
Posts: 782
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


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


Member
Joined: Jul 2004
Posts: 9,080
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


Member Spotlight
togol
togol
NW In. USA
Posts: 421
Joined: September 2005
Show All Member Profiles 
Featured:

2017 NEC and Related
2017 NEC
Now Available!

Shout Box
Powered by UBB.threads™ PHP Forum Software 7.6.0
Page Time: 0.011s Queries: 15 (0.002s) Memory: 0.7527 MB (Peak: 0.8800 MB) Zlib enabled. Server Time: 2017-05-27 21:17:31 UTC