Power Management System

[Jack R]

Help!

Another member asked a question within a thread that wasn't answered. I sent them a PM trying to answer the question the best I could but know my answer was weak.

Question was; will a Power Management System protect the Moho the same as surge guard will.

My answer was no. Than tried to explain what the PMS does could someone please explain the function of what the PMS does so I can learn also.

thanks,

jack

[gripper]

Quote:

Originally Posted by Jack R Help! My answer was no. jack

Jack, you are correct! The Power Managent System is designed to turn off (shed) various appliances, if the power use exceeds the power supply. For instance, I require a 50 AMP supply, to adequately operate all my systems. If the camp only has a 30 AMP supply, I can still operate (providing I attach the 30 AMP adapter). I just run one A/C. The PMS will shed appliances if I start approaching the 30 AMPS. In fact, once, I had to operate my fridge on LP, because the PMS shut off the power to it.
But....I have purchased a 50 AMP surge guard, because the PMS will not provide protection in the event of a surge or drop in power, at the supply side. A surge could burn or damage some of your systems, no matter what the PMS is doing.

[RJay]

Jack,
Here you go, taken from my EMS manual.



The EMS is turned on by the presence of 120VAC, or 240VAC at the L1 or L2 inputs (J6, pin 3 and 1 respectively). This feature is intended to prevent the EMS from drawing current from the +12VDCbattery supply when not in operation.


When 120 VAC or 240 VAC power is applied, the system automatically powers up and determines the nature of the power source. There is a two-minute start-up delay built into the system to prevent short-cycling of motor driven loads. During this delay period, the Load Meter display will exhibit rotating segments, indicating to the user that the system is in the delay mode. After the initial two-minute delay, the unit will apply power to controlled loads sequentially, with a one-second delay between each load to prevent power surges generated by simultaneous application of all loads.


If the generator is running, 120 VAC will be present at the L1 and L2 inputs and a +12 VDC signal will be present at J2 pin 2 on the Control Module. The EMS will assume that 120 VAC, 45 or 60 Amp Genset power is available and the energy management feature will be enabled. The Control Module sends a signal to the Display Module causing the load meter to display actual load current, the GENSET service indicator to light and all power status indicators to light.


The generator source mode takes priority over all other modes; that is, if the generator is running, the EMS will operate in that mode independent of the presence of other sources.


If 120 VAC is present at the L1 and L2 inputs and no +12 VDC signal is present at J2 pin 2 on the Control Module, the will assume that 120 VAC, 30Amp shore power is available and the energy management feature will be enabled. If only 20Amp service is available, the user must select the 20AMPservice mode by momentarily pressing the 20/30Amp select switch on the Control Panel.


If 240 VAC, 50 Amp service is available, the energy management feature is disabled and all control relay contacts are closed, energizing all of the controlled loads. The Control Module sends a signal to the Display Module which causes the load meter to go blank, the 50AMPservice indicator to light, and all power status indicators to light.


Initially, the control turns all loads on with a one-second interval and the total current is monitored. If the total current should exceed the service limit, the system will turn off the first load in the shedding table. As it turns the loads off, it calculates the amount of current that was removed, which is the value for that load. This value is placed in memory. If the current remains above the service limit, the system will turn off the next load in the shedding table. Again, it calculates the amount of current that was removed and places the value for that load in memory. The system continues to turn off loads until the total current falls below the service limit, or all of the six controlled loads have been shed. Through this process, the system has "learned" the amount of current that each particular load draws. This feature compensates for the differences in current draw over a range of line voltage and ambient temperature, by re-learning the load each time it is turned off or "shed".


The EMS now waits until the total current is lower than the service limit and enough current is available (as compared with the amount in memory for the last load shed) before it will turn that load back on. This assures
that there is sufficient current to operate the load.


NOTE: There is a two minute minimum delay period after a load is shed before the load will be turned back on again, to prevent air conditioners from turning on with a head of pressure.

[Jack R]

Thank you for the responses. It appears the PMS and EMS have the same function but different names.

jack

[SUMDALUS]

It's easy to see where much of the confusion about "what does what" comes from. Even I am confused by what Jack R was originally referring to.

The manufacturers of the different RV electrical "protection" equipments have really confused many of us because of their indescriminate use of product names/descriptions.

For example:

TRC's "protection" equipment is referred to as a Power Protection Device.

Progressive Industries'"protection" equipment is referred to as a Electrical Management System (EMS).

Intellitec's "protection" equipment is referred to as a Energy Management System (also an EMS).

Only the TRC and Progressive Industries products are similar in function. The Intellitec product does entirely something else .

Obviously, it behooves all of us to include the manufacturer's name when referring to any sort of "protection" equipment.

Hope this helps.

[Dr4Film]

Quote:

Originally Posted by Jack R It appears the PMS and EMS have the same function but different names. jack

I always thought it was only our DW's were the only ones with PMS and now I find out that our coaches have PMS too!

OMG !!!

ROFLMAO

Dr4Film ----- Richard.