Espresso machine light flicker

[danickstr]

A truly annoying espresso machine may be acting up, or else it just is designed wrong. Every six seconds it draws current enough to light up the surrounding lights for half a second. Why would a maching be designed to have a six second half a second cycle?

It is Italian BTW and the model is Francis Francis. I will get the brand name.

 

[brian john]

To keep the liquid hot, I would assume. The manufacture does not know what type of distribution system you are installing his equipment on.

Espresso Coffee drinkers like their brew strong and hot.

 

[e57]

Nevermind it's cycle - what about this?

~it draws current enough to light up the surrounding lights for half a second.

"surrounding lights" - Unrelated lighting "illuminates" during this cycle? Lights that were OFF come ON? Or lighting that was ON or dimmed gets brighter? If either, I would be checking the neutral connections through that branch circuit, and all the way through to the main and/or service drop.

High current can cause a 'dimming' effect on circuits from an under sized feeder or from loose ungrounded conductors. Enough to cause some voltage drop. But if lights are getting 'brighter' in any way, it is possible that you may have a loose neutral. When you add multi-wire circuit loads - it will change the load balance, and the voltge of each phase. If it is slight, it is a clue to trouble ahead, if it is drastic you have a fire hazard.

 

[tallgirl]

Nevermind it's cycle - what about this?


"surrounding lights" - Unrelated lighting "illuminates" during this cycle? Lights that were OFF come ON? Or lighting that was ON or dimmed gets brighter? If either, I would be checking the neutral connections through that branch circuit, and all the way through to the main and/or service drop.

High current can cause a 'dimming' effect on circuits from an under sized feeder or from loose ungrounded conductors. Enough to cause some voltage drop. But if lights are getting 'brighter' in any way, it is possible that you may have a loose neutral. When you add multi-wire circuit loads - it will change the load balance, and the voltge of each phase. If it is slight, it is a clue to trouble ahead, if it is drastic you have a fire hazard.

In a 120/240 system, if there is a high load on the A phase causing the voltage on A to drop, the voltage increases on B. Work out the voltage drop and you'll see how that can happen.

 

[dbuckley]

Why would a maching be designed to have a six second half a second cycle?

Thats classic burst fire power control.

There are two ways you can use a SCR or Triac to control power. The most commonly encountered method is phase shift, as used on dimmers. The disadvantage of phase shift with SCRs is that it generates a lot of interference, which should be suppressed.

Burst fire switches the controlled element on for whole half-cycles, and switches at the zero cross point in the half-cycle so there is no interference. The ratio of on-to-off times is the ratio of the power into the load, so half a second every six seconds is about 8.3% power on average. A heating load can integrate the on-offs into a continuous level of heat, in a way a light bulb never can.

Lots of things with thermal inertia that need power control use burst fire (or burst mode) control.

 

[e57]

In a 120/240 system, if there is a high load on the A phase causing the voltage on A to drop, the voltage increases on B. Work out the voltage drop and you'll see how that can happen.

As you would be loading both phases equally - or should be - on a piece of equipment like this, voltage drop due to load should be equal. (And should be minimal at best, unless the main, feeder or transformer is significantly under-sized) If any phase voltage rises, the neutral point is floating between the phases away from the grounded conductor. And a tell-tale of a resistive or disconnected nuetral at the sub, main panel, or transformer. As this should be an individual branch circuit, other circuits should not be affected like this IMO. (If this were a wye system the same would be true, but affect the phases differently.)

Load balance can also cause this, but the unbalance would need to be pretty significant +/or the transformer extremely undersized to even notice something like that IMO.

I would be interested to hear what the OP finds out about this.

 

[danickstr]

I did immediately check the neutrals in the panel, but I am not going to go through every Jbox in the house at this point, since my guess is that a BWMC is the culprit, combined with a bad machine circuit design that throws 1100W on and off at whim without any buffering.

I have advised them to have the unit checked, and if it is OK, to either consider returning it, or living with it, or paying me to wire a dedicated circuit to that receptacle, if a temporary wire (Orange construction cord) run to the panel fixes the problem.

And it was a bit of brightening on the currently energized lighting, to answer the question.

edit: thakns for the replies

 

[e57]

I am assuming this is a 120 residential machine? On a 120/240 residential service? And you're sure the lights were not getting brighter due to the load going "off"? (Dimming while on... The same phase) Are the lights on the same circuit or same phase? (One would assume that this is a 20a countertop circuit - not shared with the lighting.)

If the lights are getting brighter while the unit is "ON" (Under load) - then it is no fault of the machine, but not something I would wait for to get worse IMO. Dimming (Same phase) is one thing - brighter (Opposite phase) is another. Dimming is an possible circuit failure - Brighter is possible involvemnent with the Fire Dept. IMO