Progressive Industries EMS - HW30 Question

[DD716TED]

I have my TT in a storage area that provides an AC power outlet. The facility is experiencing low power (105VAC +/- 3 V) at the 5 outlets furthest (200 ft plus) from the breaker panel due line loss which happens to be me! They are going to rewire the outlets to correct this problem but in the mean time the installed PI EMS in my trailer keeps cutting power off whenever the power drops below the systems limits and then 90 seconds later restores it only to repeat the event if the power is still low. Sometimes the power will stay above the cut off limit on for various periods of time and the drop again when power drops below the EMS limit. QUESTION?? If I turn the switch on the Progressive Industries EMS Remote to OFF, does this disable the EMS system and let whatever power is available pass on through it? Nothing in the trailer is on except a small 350 watt heater and the power distribution/battery maintainer panel.

[Ralph_Cramden]

Get an autoformer.

[MEXICOWANDERER]

The key of course is why you need or do not need the heater

Plus

If you can manually switch off the house batteries at the batteries (i.e. maintenance charging)

[Bobbo]

time2roll wrote:

sgfrye wrote:

Bobbo wrote:
Let the EMS do its job. There is no harm in it cutting off the low power.

X2 this is what it is designed to do

So as it cycles every 2 minutes 24/7 for a few months.... no concern for wear and tear?

If the power is THAT bad, you need to either store your RV somewhere else, or store it not plugged in at all. Power THAT unstable is negligence.

[time2roll]

sgfrye wrote:

Bobbo wrote:
Let the EMS do its job. There is no harm in it cutting off the low power.

X2 this is what it is designed to do

So as it cycles every 2 minutes 24/7 for a few months.... no concern for wear and tear?

[sgfrye]

Bobbo wrote:
Let the EMS do its job. There is no harm in it cutting off the low power.

X2 this is what it is designed to do

[ktmrfs]

CA Traveler wrote:

time2roll wrote:

ktmrfs wrote:
with the switch off it will likely ignore the high voltage shutdown and won't shut down at the 105V but it WILL repeat WILL shut down if the voltage goes much below the 105, somewhere around 95-100 it WILL shut down.

I need to bust out my variable transformer and check this out 😉

Please post the results.

I'm also wondering if it shuts down not because it's protecting from low voltage but because the voltage is below it's operating voltage to switch the relays? My 14 years old unit manual refers to a voltage range of 78-255V. I should add that I have a HW50C and not the HW30C per the thread title.

yes it's the relay operating pull in and drop out voltage that determines when it will operate when in the OFF position since the relay is a NO (normally open) relay, it needs a voltage applied to the coil to close the contacts.


I (and others) have experienced this when having a marginal generator to start an AC unit. what often happens is that generator voltage drops, relay kicks out, generator voltage then rises, relay kicks in, voltage drop, relay kicks out . Goes in and out probably 5 x per second, just buzzes away. with two honda 2000's in eco mode, I've had it chatter like crazy since the generator can't ramp up out of eco mode fast enough. switch them out of eco mode and it isn't an issue.

If the unit is in the ON position, don't recall it chattering, since it if it drops out, it then should wait the required time before trying to kick in again. It's in the OFF position that can be an issue. the internal relay on at least the 30A unit, like most relays has a pull in and drop out voltage spec. and if you get caught where it pulls in then the load drops it below the hold in it starts chattering.

with the unit OFF, the drop out voltage is less than the 105V spec. Since the pull in voltage has to be less than 105V guaranteed for the unit to operate as specified, the drop out voltage must then be below the pull in voltage,so 100V or less. How much less likely depends on the particular relay. In the ON position the control logic drops the relay out, in the OFF position your relying on the voltage staying above the min hold in voltage.

I've never hooked my variac up to see the exact pull in and drop out voltages on my unit. I just know it is something below 105V to drop out when not in eco mode.

and with the typical variation in this type of relay, one unit may drop out a 95V and the next one at 80V, there is often quite a variation and a wide spec.

[CA_Traveler]

time2roll wrote:

ktmrfs wrote:
with the switch off it will likely ignore the high voltage shutdown and won't shut down at the 105V but it WILL repeat WILL shut down if the voltage goes much below the 105, somewhere around 95-100 it WILL shut down.

I need to bust out my variable transformer and check this out 😉

Please post the results.

I'm also wondering if it shuts down not because it's protecting from low voltage but because the voltage is below it's operating voltage to switch the relays? My 14 years old unit manual refers to a voltage range of 78-255V. I should add that I have a HW50C and not the HW30C per the thread title.

[RSD559]

Why not leave the trailer unplugged, and just snake an extension cord in for the little heater? Everything is out of harm's way, except for the little heater.

[time2roll]

ktmrfs wrote:
with the switch off it will likely ignore the high voltage shutdown and won't shut down at the 105V but it WILL repeat WILL shut down if the voltage goes much below the 105, somewhere around 95-100 it WILL shut down.

I need to bust out my variable transformer and check this out 😉

[time2roll]

All the more reason not to use bypass unattended such as storage.

Especially because if the relay drops out for low voltage without the delay circuit it would be easy for conditions to create very rapid switching on/off/on/off. BTDT with my Frank's Booster.

[ktmrfs]

time2roll wrote:
I would skip the 350 watt heater. Not really enough to do anything anyway.

Otherwise yes the bypass switch will cause the EMS to ignore voltage. I would sooner just unplug and disconnect the battery to resolve the storage issue.

no, the bypass switch will NOT completely ignore the voltage. with the switch off it will likely ignore the high voltage shutdown and won't shut down at the 105V but it WILL repeat WILL shut down if the voltage goes much below the 105, somewhere around 95-100 it WILL shut down.

I know that for a fact. the big relay that is used to apply power has a minimum pull in and drop out voltage spec that is around 100V. even with the swich off if the relay doesn't see the minimum pull in, or goes below the drop out, it WILL kick out. the pull in voltage is higher than the drop out.

that pull in and drop out voltage is completely independent of the other control circuits in the EMS.

[time2roll]

I would skip the 350 watt heater. Not really enough to do anything anyway.

Otherwise yes the bypass switch will cause the EMS to ignore voltage. I would sooner just unplug and disconnect the battery to resolve the storage issue.

[SoundGuy]

CA Traveler wrote:
After the changes are completed check the plug very carefully for voltage, polarity, etc.

I'm sure CA Traveler means "check the receptacle". Sure, once this work is completed it won't hurt to double check yourself that the wiring has been done correctly, but regardless your EMS should prevent incorrectly wired power from reaching your trailer anyway.

[CA_Traveler]

Never ever leave a RV connected to shore power when you know they are/may be working on the system regardless of what protective devices you have. Unplug and stow the cord so someone can't plug it back in and disconnect the battery. Not doing this exposes you to high/low voltage and/or faulty wiring.

After the changes are completed check the plug very carefully for voltage, polarity, etc. Recommend you then plug in a heater for load and recheck.

Yes most of the time it will be OK. But there are posts about it NOT being OK.