PowerLine EMS Problem

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Art In Mobile

Art In Mobile

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Joined
Jan 5, 2009
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372
This has been a problem from new day one! When I have 50 amp service (240 volts) The Display should show 50 Amp & the load meter should go blank. It never goes off of 30 amp! I have 240 volts going to L1 & L2 on the PowerLine Module.  I have checked all threw from the transfer switch to the breakers & 240 volts is their. The Neutral line checks out. The green LED is lit on the module but still shows 30 amp. At first I thought All the parks had a problem! Fuse is good in control module. The load meter seems to be showing proper amps but it is not supposed to be showing anything in 50 amp mode according to page 3 of manual.
Am very knowledgeable with electrical things but this one got me. Could be the module. Any guesses? Thanks  Art
 
Ron
Thanks for the response. I considered that also but as it never shows 50 amp on the display, something is wrong. It is not shedding any electrical loads that I know of. It should be as it thinks it is in the 30 amp mode all the time. It has the ability to shut down a rear A/C if you have 2 roof airs by interrupting the low voltage (thermostat) power & can shed electric water heater & washer/dryer. It has one 20 amp relay & one 10 amp relay for 120 volt AC loads. Also has 2 low voltage relays to shed loads like controlling an air conditioner by opening the thermostat circuit. With the DIP  switches you can chose what order you want to shut down loads if you are on 30 amp service.
    So really 2 problems, as it thinks I am on 30 amps, water heater, washing machine or something should be shut down. Everything is working. It should also show on the display 50 amp service.
I sent e-mail to the company. Will let you all know if I get any results. Art
 
It sounds like a error in the panel read out Ron.  If you haven't already, try this.  Turn on your electric water heater element, both A/C units, and your microwave.  If the EMS is working, it should shut off the water heater element.  If you pop a circut breaker in the panel, then the EMS is faulty.  I would bet that the panel readout circut board is bad. If all is working well in the coach, then most likely the appliances are getting the required voltage.  Question, when you do plug into 30 volt service, does the voltage window on the panel show the current voltage draw? 

It should show the current draw and increase with each appliance that you switch on. 

Sarge
 
Art - either something is wrong with the EMS, or something is wired wrong.  Give them a phone call Monday - it will be more productive if you talk to them.
 
SargeW
Good question! I just went out and plugged into the 30 amp plug. Yes it shows the amp draw when I plug into 30 amps instead of 50. All electrical circuits are operating properly. I will give John's suggestion a try and call them if I do not get an e-mail response. Thanks for your help. Art
 
The Intellitec Powerline EMS may not be seeing 240V at its L1 & L2 terminals, which is where it senses the type of power available. Here is a quote for the service manual:

If 120 VAC is present at the L1 and L2 inputs and no +12 VDC signal is present at J4 pin 8 on the
Control Module the EMS will assume that 120 VAC, 30 Amp shore power is available and the energy
management feature will be enabled.
Click to expand...

The good news is that usually won't shed loads if it thinks you have 30A when you actually have 50A because the current sensor will not see an accurate reflection of the actual load when there is 240v present. That's because it measures at the combined neutral rather than summing the two hots.

You can download the manual here: http://www.intellitecsve.com/PDF/5322100.100.pdf

Have you tried the generator mode to see if that reads correctly (lights up the Generator indicator and shows the current being used)?
 
Gary
When I run the generator all is OK. Gen light on EMS display panel lights up. I do read 240 volts to the 2 terminals that require it on the EMS module.
When an appliance like a 240 volt clothes dryer is using  L1 & L2 the neutral white wire will not show amps as the current is going back & forth between L 1 & L2. I guess that is why they have the amp readout go blank on the display in 50 amp mode. But when I am using say L1 for the hot water heater & L2 for the refrigerator the white wire is carrying all the combined load threw the amp sensor even though I am on 50 amp service. I am only drawing 120 volts but on two circuits. I like being able to see amp draw on 50 amp which on mine stays on in 50 amp mode even though the manual says it should not. Other than the fact it never registers 50 amp I guess I don't have a big problem. I tried with the gen on to overload with hot water heater, basement air, & all things on at once but the Onan could handle it so nothing was shed. I will have to try it on 30 amp service shore power. Thanks Art
 
But when I am using say L1 for the hot water heater & L2 for the refrigerator the white wire is carrying all the combined load threw the amp sensor even though I am on 50 amp service.
Click to expand...

When you are using 120v appliances (and I doubt if you have any 240v appliances onboard, including the dryer) - the neutral carries the algebraic sum of the current in the two hots (L1 & L2). They are 180 degrees out of phase with each other, i.e. one is plus when the other is minus, so if the L1 and L2 currents are equal the neutral shows 0 amps. If L1 was +30A and L2 -20A, then the neutral would show +10.

Here is a thought: check to see if you have +12v at J4 pin 8 when you are on 50A shore power. That might confuse it (J4-8 is used to detect the generator running, but it doe snot expect to have 240V on L1-L2 if that is the case. J4-8 is normally wired to the generator switch "on" indicator so that it activates only when the genny is running. Maybe you are getting some 12v feedback into that circuit???
 
Lemme ask this about that: What does the EMS, or the coach for that matter, expect to see; in-phase (both legs) 120v to neutral, or single-phase 120/240V. Obviously in-phase 120V is the default because that's what a dogbone produces. Does it care?
 
What does the EMS, or the coach for that matter, expect to see; in-phase (both legs) 120v to neutral, or single-phase 120/240V. Obviously in-phase 120V is the default because that's what a dogbone produces. Does it care?
Click to expand...

The two Intellitec EMS systems commonly seen in coaches both use the same logic to determine what type of power is available. If it sees 240v across the two legs, it says "50A service" and it does NOT attempt to manage loads or display amps. If it sees in-phase (0v across the legs, 120v to neutral) it says "30A service or maybe the generator is running". A further test for 12v on pin J4-8) allows it to decide between generator and 30A shore power.  The extra test is necessary because the most common large generators, e.g. the Onan Quiet Diesel 7.7 and 8.0, generate 30+ amps on both legs but it is in-phase 120v. If the EMS detects the generator running (+12 on J4-8) then it stops the power management function but continues to display the amps measured on the neutral.

The EMS can't tell the difference between 30A and 20A or 15A, so a switch is provided to tell it to manage to a lessor amp load (20 instead of 30).

The rest of the coach doesn't care, in the sense that it blithely consumes amps as needed until a breaker trips somewhere, e.g. attempting to run 2 a/c units when only 30A is available. The purpose of the EMS is to manage loads so that breakers don't trip.

A few coaches (Newells & some Wanderlodges and Prevost conversions) may have residential style electric ranges that require 240v. These care about voltage. They have 240v generators so they can run the genny if standard 240v/50A shore power is not available.
 
Gary
I think you hit on something. Something else I noticed goes along with your quote

(When you are using 120v appliances (and I doubt if you have any 240v appliances onboard, including the dryer) - the neutral carries the algebraic sum of the current in the two hots (L1 & L2). They are 180 degrees out of phase with each other, i.e. one is plus when the other is minus, so if the L1 and L2 currents are equal the neutral shows 0 amps. If L1 was +30A and L2 -20A, then the neutral would show +10.)

I have noticed that most of the amp readings at the display are fairly accurate. Except when I run the basement air. Then it reads to low. I bet it is subtracting the 180 out of phase amps being used on the other leg! This is happening  when I know I am on 50 amp service but the display is showing 30 amps. Does this new info help you to better diagnose the problem? Thanks Art
 
Remember that this is AC, not DC, so there aren't polarity issues here. Yes the phases are 180 degrees out, but in this case that means that they are returning their loads back to the neutral at different times. I looked at mine with an amp clamp last weekend alongside the EMS coil and it is very close.

Gary, thanks for the info. We rarely go to hookup CG's and I hadn't thought that through much.
 
I have noticed that most of the amp readings at the display are fairly accurate. Except when I run the basement air. Then it reads to low. I bet it is subtracting the 180 out of phase amps being used on the other leg! This is happening  when I know I am on 50 amp service but the display is showing 30 amps. Does this new info help you to better diagnose the problem?
Click to expand...

Doesn't really help, since that is normal operation. The EMS reads the amp load on the neutral wire, so it sees only the combined effect of the two legs. For practical purposes, when on 50A any amp load on L2 will be subtracted from that of L1 (as far as the metering is concerned).

It may be that your display is bad or miswired some how, i.e. displaying 30A when 50A indicator is called for.  I'd suggest contacting Intellitec about the problem - they are generally helpful folks and have done well for me in the past (that's why I am intimately familiar with the EMS!). Explain that you have measured 240V at L1/L2 and the display still says 30A and see what they say.

http://www.intellitec.com/contactus.htm
 
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