Progressive Industries EMS - HW30 Question

Get an autoformer.

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)

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.

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?

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

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.

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.

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.

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 ;)

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.