Wanderlodge Owners Group  
BuyByeBlueBird.com
Donate

Go Back   Wanderlodge Owners Group > Mechanic's Corner > Generators

Generators In this forum we will try to answer any of your questions about the different model generators that can be found on Blue Bird coach's.

Site Search:
Reply
 
Thread Tools
  #1  
Old 08-25-2013
overthehump's Avatar
overthehump overthehump is offline
Senior Member
 
Join Date: Nov 2012
Location: Lovington
Posts: 272
Default One legged 10K Powertech

Hope this is in the right forum. I'm in need of a competent tech that can trouble shoot our powertech generator on our 1994 BMC. I've tested everything that I know to test to figure out why the generator will only run one AC. Here's the symptoms.

The front AC will run perfectly and cool. You can turn on the rear AC and the fan will come on but after 3 minutes, when the compressor tries to come on, the contactor on the Auto Transfer switch will kick out. Volts on both legs before gen is loaded is 125v. After front AC is running voltage is 131v for front leg and 119v for rear leg. I visited with Jeff @ Powertech and he said this is about normal for a 240v Powertech 10K generator. All the grounds I could find leading to the gen were cleaned and checked.

Both AC's run fine on shore power.

1. Picture of both AT switches with shore power and gen power coming into the switch on the left. Shore power comes in on the right, gen power on the left, bottom of the switch.

2. Picture of right switch with gen and shore power coming in on the bottom.

3. Picture of the left switch with load coming out of the bottom

I've moved the gen leads from the AT switch on the left to the one on the right to make sure the contactor was working correctly (wired gen coming into top of contactor on the right). Same problem – only one leg will run the AC. It doesn't matter which way you have it hooked up either. If the legs are switched, the rear AC will run and the front AC will shut off when the compressor tries to kick in.

After switching leads around in various configurations I believe we've concluded that the AT switches are good. They'll work on shore power but not on the generator (only 1 leg will work correctly). So, I think my next step is finding a good generator tech that can check it out for me. I'm looking for recommendations. We'll be heading west from southeast NM to the Grand Canyon the middle of Sept and hope to make it to Quartzite in January.
Attached Thumbnails
Click image for larger version

Name:	P1030512.jpg
Views:	134
Size:	42.7 KB
ID:	24412   Click image for larger version

Name:	P1030508.jpg
Views:	126
Size:	43.5 KB
ID:	24413   Click image for larger version

Name:	P1030511.jpg
Views:	130
Size:	45.2 KB
ID:	24414  
__________________
Ron & Patsi Humphrey
Lovington, NM
1994 BMC 37'
2010 Jeep Wrangler Mountain
Reply With Quote
  #2  
Old 08-25-2013
Dieselbird01's Avatar
Dieselbird01 Dieselbird01 is offline
John Wyatt – Administrator/Moderator
 
Join Date: Feb 2008
Location: Titusville
Posts: 4,029
Default

Hi Ron,

Have you verified that both sides of the main circuit breaker in the generator control box are good and can carry a heavy load? No loose or burnt wires in there?

Good luck
__________________
John Wyatt
Titusville, Florida
1991 40' WLWB-WTB
Body Number F095567
My Location: http://www.bbirdmaps.com/user1.cfm?user=4

1991 40' WB ...From 2008 - Present
1984 ½ PT-36 .From 2000 - 2008
1973 FC-31 .....From 1991 - 2001
Reply With Quote
  #3  
Old 08-25-2013
warbucks13477's Avatar
warbucks13477 warbucks13477 is offline
Senior
 
Join Date: Jun 2008
Location: Vernon Center
Posts: 1,302
Default

doesn't make any sense that it runs on shore power but not on you generator. Turn off the good a/c amd then see if the one that kicks off runs fine. you may have some diodes gome bad in the generator and it will not supply current enough to run that a/c?
__________________
Tom Warner
Vernon Center,NY
1985 PT40 SOLD
6V92
Reply With Quote
  #4  
Old 08-25-2013
overthehump's Avatar
overthehump overthehump is offline
Senior Member
 
Join Date: Nov 2012
Location: Lovington
Posts: 272
Default

Quote:
Originally Posted by Dieselbird01 View Post
Hi Ron,

Have you verified that both sides of the main circuit breaker in the generator control box are good and can carry a heavy load? No loose or burnt wires in there?

Good luck
No loose or burnt wires there. I haven't check the circuit breaker on the gen. Do you remove the control box cover and check the leads below the main breaker?
__________________
Ron & Patsi Humphrey
Lovington, NM
1994 BMC 37'
2010 Jeep Wrangler Mountain
Reply With Quote
  #5  
Old 08-25-2013
overthehump's Avatar
overthehump overthehump is offline
Senior Member
 
Join Date: Nov 2012
Location: Lovington
Posts: 272
Default

Quote:
Originally Posted by warbucks13477 View Post
doesn't make any sense that it runs on shore power but not on you generator. Turn off the good a/c amd then see if the one that kicks off runs fine. you may have some diodes gome bad in the generator and it will not supply current enough to run that a/c?
I agree...it doesn't make sense. Doesn't matter if the front AC is on or not. Rear won't come on, other than the fan. But when compressor tries to come on the fan will quit also.

I've been stumped all summer.
__________________
Ron & Patsi Humphrey
Lovington, NM
1994 BMC 37'
2010 Jeep Wrangler Mountain
Reply With Quote
  #6  
Old 08-25-2013
warbucks13477's Avatar
warbucks13477 warbucks13477 is offline
Senior
 
Join Date: Jun 2008
Location: Vernon Center
Posts: 1,302
Default

Ron two more questions. first has it run this way since you have had The coach? second has anythimg been done to the a/c wiring since you have had the coach?
__________________
Tom Warner
Vernon Center,NY
1985 PT40 SOLD
6V92
Reply With Quote
  #7  
Old 08-25-2013
overthehump's Avatar
overthehump overthehump is offline
Senior Member
 
Join Date: Nov 2012
Location: Lovington
Posts: 272
Default

Quote:
Originally Posted by warbucks13477 View Post
Ron two more questions. first has it run this way since you have had The coach? second has anythimg been done to the a/c wiring since you have had the coach?
It's been this way since I've had the coach. Nothing done to the wiring. Previous owner said he'd replaced the Auto Transfer switch on the left in the picture with the two switches shown.
__________________
Ron & Patsi Humphrey
Lovington, NM
1994 BMC 37'
2010 Jeep Wrangler Mountain
Reply With Quote
  #8  
Old 08-25-2013
gcyeaw's Avatar
gcyeaw gcyeaw is offline
Gardner
 
Join Date: Dec 2007
Location: Ridgewood
Posts: 8,942
Default

OK I am speculating here, but worth consideration.

I assume the default for the transfer switch is shore power and the presence of generator power will initiate a transfer. If that is so, then the start up load of the rear AC may be greater than the front unit and the voltage dip is causing the transfer switch to drop back to the default shore power mode.

I believe the transfer switch may be the culprit. Is there a built in delay to prevent the switch from changing status back and forth too quickly preventing sudden loads from causing it to falsely detect the dip as the absence of generator voltage? If the switch default is shore power then the start up load would not effect the switch status while using shore power.

Another possibility is the generator regulator is not adjusting the output quickly enough causing the switch to falsely detect the absence of generator voltage.

Why did the PO install the new switches in the first place and are they the correct units for the intended load.
__________________
Gardner Yeaw
86 PT-36 Golden Memories
83FC35 SB $IXTEEN TON$ SOLD
78 FC 33 Happinest (Sold)
Ridgewood, New Jersey
Reply With Quote
  #9  
Old 08-25-2013
konehd konehd is offline
Senior Member
 
Join Date: Jan 2008
Location: Sedona
Posts: 1,777
Default

Gardner's right, there is a delay between switching to the gen. I believe its the circuit board under one of the contactors in the second photo.

One thing to check is the contactors. You can ohm out the contacts with a meter buy pushing in the armature and reading the resistance between the contacts.

Of course make sure there is no voltage on it!! Unplugged from shore, gen off and inverter off.

Usually you can get a contact kit for them if they are bad, or take them out and file them...


HTH, Joe
__________________
Joe & Pat Garner

'93 WB40, Alligator - Sold
Sedona, AZ
Still having fun- even though the the BlueBirds Away!
Reply With Quote
  #10  
Old 08-25-2013
overthehump's Avatar
overthehump overthehump is offline
Senior Member
 
Join Date: Nov 2012
Location: Lovington
Posts: 272
Default

Took the switch out, took the contacts out. They didn't look that bad but I filed them anyway. Put the contacts all back together and will reassemble the switches and wiring in the morning. Don't know if it will make a difference but I have my fingers crossed.
__________________
Ron & Patsi Humphrey
Lovington, NM
1994 BMC 37'
2010 Jeep Wrangler Mountain
Reply With Quote
Reply

Bookmarks

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
PowerTech won't crank over jwmp Generators 4 06-14-2012 11:30 AM
Powertech Overheat Terry Hester Generators 9 08-30-2011 11:05 PM
Three Legged Dog Bill Pape Under The Awning 18 01-14-2011 12:46 PM
SOB powertech 6.6kw techson Generators 46 08-19-2010 08:43 PM
powertech generator Randy Dupree Generators 16 01-28-2009 11:38 PM

Web Search:

All times are GMT -4. The time now is 07:28 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, vBulletin Solutions Inc.