Progressive EMS-HW50C unit
We have Porgressive EMS-HW50C about 1.5 years old and hardwired at the dealership into our new camper. Yesterday about 1:00 a.m. we heard this loud tapping noise. We thought we had a large rat in ou...
Forum Discussion
SoundGuy wrote:brulaz wrote:
I thought these things are not supposed to chatter when the line voltage momentarily drops?
Conventional line source power rarely drops "momentarily" but rather sags, in which case the EMS will disconnect power completely until the line voltage once again rises above the low voltage threshold. Although the OP didn't specifically say he inferred that he was running on genset power at the time, in which case the genset was likely struggling to meet the load which was varying as different devices in the rig cycled on/off ... unfortunately a classic case of too little precise information on which to base a solid conclusion. Having heard this chattering myself though my bet is that's exactly what was happening, the simple solution being to put the unit in bypass, especially when it's not needed when running on genset anyway.Think mine has a 120s delay before it comes back on.
This can be reduced though.
Depends ... if yours is a Progressive hardwire EMS then the delay can be set to either 15 secs or 2:16, if it's a portable Progressive EMS then it's fixed at 2:16. TRC units have a fixed 128" delay.
that delay is for complete loss of input power, a voltage sag doesn't (at least on mine) trigger that delay. It causes the relay to drop out. When it does that it does NOT trigger an error message. the Low voltage error will only show up if it detects low voltage during initial connection or a much longer drop than I've experienced with the "generator chatter" problem. It would be better IMHO if the EMS unit (a) had the ability to stay connected down to say mid 90V for 3-5 seconds, and (b) a 3 or 4 second delay after trip out before the contacts go back in.
As it is, they have a very simple circuit on the input 120V relay to set the input voltage limit to near 104V with almost no hysteresis. Off at 104, On at 104, rather than say off at 104 not back on till 110 or something.
And bypassing with the switch will NOT solve this problem. the low voltage trip will stay enabled. the switch just disables the reversed polarity, open ground, open neutral, etc.
