-
Unbalanced line voltage
I have a 2001 Liberty XL II.
I am having unbalanced line voltage readings at the voltage meters
when plugged in to 50 amp line. Line one is about 104 volts and line 2 is about 108.
no matter where I am plugged into get same readings. Never get 110 readings or higher.start generator and line readings same with min load on gen i.e. Just inverters on
transfer switch is working.
question is where are the meters measuring the voltage?
is the problem in transfer switch.the cruisairs hate low voltage and I am getting a low voltage warning on the cruisair panel.
-
14 Replies
-
William,
My first reaction is if you used a quality tester to measure the actual line voltage inside the coach such as at an outlet to verify the voltage into the coach is in fact as low as describerd.
If the generator and shore power voltage readings are the same low actual values and the actual voltage at the shore or generator is the normal 120 my first step would be to start sniffing around for something very hot or burning because that voltage drop with good incoming power is a sign of something with very high resistance and high resistance means heat.
-
The more I think about it the more concerned I get.
Shore and generator power both come into the transfer switch so I would start there measuring voltages. Beyond that the AC power I believe goes directly to the electrical panel bus bars. If the voltage drop is between the two power sources and the panel something seems very wrong.
-
Are the voltages measured before or after the inverters?
If after and the inverters are not pure sine wave, then the
measurements will be affected. Depending on the measuring instrument, a stepped
output inverter can cause problems. -
On a Liberty they are reading the default voltage and if no shore or generator power the default is inverter, then shore power then Generator. The highest and best voltage is the default, so if connected to shore power and the generator is running the generator is powering the coach AC system (AC as in alternating current)
-
Get a quality volt meter and carefully measure the voltage at the pole and see if you have a difference between incoming power (at each leg) and what’s inside the coach. You can use that to determine what to investigate next.
I do quite a bit of writing and executing of installation qualification protocols for industrial equipment and I always verify the incoming line voltage before plugging in the equipment. You would be suprised how many times I see a wall plug that is not what I was expecting 🙂 Nearly always, in my experience, it’s the power company!
-
I’m just curious and it may be a clue, but what is the voltage reading with the shore power disconnected and generator off?
1999 XLV X-6872, liberty #440 -
Jon
I will have to check the voltage at the outlets in the coach. I have checked voltage at 50 amp box and each leg is 120V. I can not say what the voltage is without power but will check this weekend
les
I have the old heart Xantrex inverters and not pure sine wave.
I too am concerned on where the volt meters get their readings. I have a feeling that it may
be related to the inverters . -
change the inverters to pure sine wave even if it’s not the problem Magnums are the choice
-
If the iverters are not pure sine wave and you are measuring inverter voltage 108 is about right for a modified sine wave inverter. The reason is the wave shape of the output voltage. Turn the inverter off if you can and measure voltage.
I suspect you are reading inverter output from a modified sine wave inverter.
-
Inverter is in pass through internally when on shore or gen power, therefor a drop from modified can not cause the issue….
Did this problem just begin?
With a voltmeter what is the reading at the pole, what is the voltage at the plugs inside the coach, if you are seeing a drop in voltage then you must carefully check at the transfer switch to see if the drop is there…If you are seeing a voltage drop I would aggressively search out the cause
-
Gys,
Lets not confuse William by pointing fingers at inverters.. His coach has the inverters set up to only power about 6 electrical circuits and as he described his issue he only shows low voltage on shore or generator power, at which point NOTHING is inverted, but the inverters are functioning as battery chargers and only pass through the incoming electric power to the 6 circuits. None of his Cruiseairs are powered by inverters.
We still don’t have enough information from William and really need voltage readings using a decent quality multi-tester to verify at which point the incoming shore or generator power steps down, if in fact it does.
He has not yet said what voltage he shows from inverters only, and if they also show the low voltage the next step is to get an actual reading from the 120V panel bus bars.
What tells me the voltage readings are correct and his problem has nothing to do with the gauges is he said the Cruiseair panels are showing low voltage.
-
Update on unbalanced line voltage:
at 50 amp pole, voltage is at 122V for both leg 1 and leg 2
With 50 amp cord plugged in , inverters on, and no AC load at load center: (all circut breakers off, so inverters not getting AC power)
Line 1 – 104 V, Line 2 -109 V, and all outlets in coach read at 118V
With generator on, inverters on, and no AC load at load center: ( no AC to the inverters, control panel on)
Line 1 – 105 V, Line 2- 107 V, and all outlets in coach read at 116V
With generator on,inverters on ,with load on line 1 @ 12, and load on line 2 @ 25 amps:
Line 1- 105, Line 2 – 107. Outlets still at 116V.
AC to inverters represent the load above, and fridge load on line one through inverters
With no cord, and no generator, Just inverters on:
Line 1 – 110V, Line 2- 114V, (fridge was on Line 1 via inverter drawing 2 amps)
When shut inverters off, and no cord or generator on:
I do not get any reading whatsoever on the panel for voltage. When I mean inverters off, it is turning them off at the control head in the panel.
So it appears that the transfer switch is indeed passing full current to load center, as the outlets reflect the correct voltage.
Appears the generators voltage regulator is set lower than the land line’s 122V, thus the 2 Volt decrease at outlets from cord to gennie readings.
Not quite sure why the Cruiseair will give me a low AC reading when they should be hard wired to the load center. This does not happen all the time, and have never had this happen in a campground or on gennie power. It happens where I store my coach. I am not sure where I sit in line with loads of other coaches, which may drop the voltage at the pole and give me such warning. With my meters at the load center not giving me accurate readings, I don’t know if I am getting less power at the pole when other coaches vary their loads ahead of mine.
I just want the voltage meter to give me an accurate read of the line voltage in my panel.
I am going to take her to Liberty in Stuart in a couple of weeks for them to sort this out.
Looks like I may be needing some new sine wave inverters!!
Lucklily I only live about 70 miles south of them.
Thanks for all the responses, and I will keep you informed when I get her back from Service.
William
-
William, I think the use of pure sine wave inverters is a good update for coaches with modified sine wave if for no other reason than to protect newer appliances that do not function well with modified sine wave power. However I don’t think your inverters are related to or affecting your voltage displays.
The fact your actual voltage readings at outlets are the same as the power from the pedestal or the generator tells me there is an issue only associated with voltage to the voltmeters in your electric panel.
Except for the volt meter readings, nothing you listed as actual voltages would be alarming so I have no fears you won’t be safe, as I would it you had the voltages at the source, such as at the pedestal and the voltages at the outlets were as low as the voltmeters show. I do wonder if you load the system such as by running Cruiseairs if the voltages at the outlets drop. The reason I say that is without loads you can get good voltage levels, but as soon as a load is applied the voltages drop. If that is the case then my next step would be to start at the transfer switch and verify everything is tight as far as connections and then open the electrical panel in the coach and make sure the connections to the bus bars are tight also. I would look carefully for evidence of high heat either by looking for dark or burned insulation or the smell of hot electrical components.
-
Sorry for the delay in getting back to you all on this topic.
Here is the update after getting my coach back from service at Liberty in Stuart, Florida.
For the unbalanced line voltage, this was traced back to faulty line voltage meters in the load center. These were replaced with 2 new meters, Part# 570-003′ @ $82.92 each. Now the line voltage reflects the voltage coming into the coach or from gennie.
For the low A/C reading on the cruisair. The board was recently replace as the numbers on the SMX control were flickering. Appears that the SMX board in the bay has a built in voltage meter. That meter was reading the voltage as 105V when it was actually120V. This was corrected by hitting off button on the thermostat controller. Then hit set, followed by pushing both up and down buttons at same time. This will give you the voltage that the board is reading from the line. Take all loads off that line that the AC is on, then take volt meter and read the actual line voltage coming into coach. I did this at the outlet by the SMX controller. Then either push up or down button till the voltage on the SMX readout equals that of the line voltage. Then push off button to reset the meter. Obviously mine was reading too low, and when load was added it would drop below the cutoff at 100V and give. The low A/C warning.
Log in to reply.