Pulsing amperage from espresso

[Pgeee]

i Have a pro installed 110v to 240v inverter toroidal transformer that runs off the generator. Does anyone know why kitchen coffee espresso makers like mine heat up the water using a system that pulses the amps. It’s annoying for my generator as it’s pulsing this load onto the generator which goes through this load no load cycle about once per second. is This bad for the generator (diesel westerbeke) or inverter , is there any solution / mitigation? Thanks

 

[dtfeld]

Is the transformer rated to run that load? It could be tripping on/off or the expresso make it pulsing the power. Hard to tell without specific part numbers. Up here, thats a pretty exotic setup.

 

[Pgeee]

Is the transformer rated to run that load? It could be tripping on/off or the expresso make it pulsing the power. Hard to tell without specific part numbers. Up here, thats a pretty exotic setup.

The transformer has a breaker which does not trip, it’s ok for at least 22 amps. I’m thinking this is down to the design of these coffee makers. They are small and they have to heat water rapidly. I.e the pulsing amps during the heating (or maybe it’s when it’s pressurising) is part of the design. So the question is more around what this is doing to my generator, the governor is having to work to increase and decrease fuel to manage these pulses and keep the generator engine at constant revs, and the front end is having to manage this pulsing draw on the electrical components. Maybe it’s not a problem but my poor old genny is 1600 hours and has been known to struggle if I load it up with too many draws (a/c plus water heater plus charging e.g). One mitigation I thought of would be to run the coffee maker off a lithium inverter pack. , which I recharge with the generator. Not efficient but less testing of my generator. One thing for sure I’m not giving up diy espresso.

 

[Bill Curtis]

Circuit breakers are normally designed for (or ruled to be by NEC) running load plus 20% . Old rule of thumb is don't use over 20% of the circuit capacity. ie: 20 amp circuit should normally not exceed 18 running amps.

That plulsing probably indicates the cofee maker uses an electronic circuit, such as an SCR, to maintain the current on the element to maintain a specific temperature. My ultr high e cooktop does the same thing.

 

[Pgeee]

Thanks for replies so far. It’s occurred to me that my 110v to 240v application may not be much of a factor, except a 240v coffee maker for the same watts would be less amps,than on a 110v system. However, next time you use your espresso machine on the boat , voltage aside, (anyone reading this) if you can and are interested, can I ask that you monitor your ammeter please , just to see if the same pulsing occurs .

 

[ttmott]

Is everything running on 50hz 240V or is it a mixed bag?
The espresso machine should be incidental to the generator's capability.

 

[dtfeld]

Run it off the inverter and see what happens. If the same pulsing, its the coffee maker.

I do run a coffee maker of of my inverter system and it works just fine, but I dont have the complexity of upping the voltage to match the local appliances.

 

[Pgeee]

Is everything running on 50hz 240V or is it a mixed bag?
The espresso machine should be incidental to the generator's capability.

its not the generator capacity I am concerned about, just the fact it has to bear these spikes and troughs , which I've determined has to be a trait of these coffee machine designs, seems it's normal.
A diesel engine should be able to handle it easily methinks , for instance many applications like excavators would be full of ups and downs in demand .
When I run the coffee maker it's the only thing running on the 240v circuit usually. In fact I usually make sure no high draw 110v stuff is running at the same time, like the water heater. I do that on purpose to be nice to be genny. But would be interesting to get some other ammeter readings from those of us who run these things on board, regardless of voltage and inverters

 

[Pgeee]

Run it off the inverter and see what happens. If the same pulsing, its the coffee maker.

I do run a coffee maker of of my inverter system and it works just fine, but I dont have the complexity of upping the voltage to match the local appliances.

Yeah i'm pretty sure it's part of the coffee maker design.

 

[Ericinmich]

I can't help with specifics, but we have a Saeco super-automatic (grinds, packs puck, makes espresso/coffee) and if home running on genny (15k) it struggles to work. Often it will complete a cycle, but a lot of times it gives up, I think while turing the motor that packs the puck. I think it monitors the current to compress the puck and it gives up if voltage is moving around much.

 

[Pgeee]

I can't help with specifics, but we have a Saeco super-automatic (grinds, packs puck, makes espresso/coffee) and if home running on genny (15k) it struggles to work. Often it will complete a cycle, but a lot of times it gives up, I think while turing the motor that packs the puck. I think it monitors the current to compress the puck and it gives up if voltage is moving around much.

hmm, maybe because it's a unit with loads of electronics it goes awry. A 15Kva genny is really meaty though, mine is only 8. Does the coffee maker work ok at home. I used to have a Delonghi fully automatic and it did go a bit weird towards the end of it's life and I think that was while packing the puck, but it was a mechanical thing. The internal mechanics were, well, very mechanical, with arms and gears and drive belts, much of it plastic. The kind of mechanisms that will surely wear out in due course.
The Sunbeam I have on the boat is a simple manual grind manual extraction unit. Sunbeam did come back to me advising that the pulsing is normal. The generator handles it , i just hope it's not shortening it's life

 

[Ericinmich]

hmm, maybe because it's a unit with loads of electronics it goes awry. A 15Kva genny is really meaty though, mine is only 8. Does the coffee maker work ok at home. I used to have a Delonghi fully automatic and it did go a bit weird towards the end of it's life and I think that was while packing the puck, but it was a mechanical thing. The internal mechanics were, well, very mechanical, with arms and gears and drive belts, much of it plastic. The kind of mechanisms that will surely wear out in due course.
The Sunbeam I have on the boat is a simple manual grind manual extraction unit. Sunbeam did come back to me advising that the pulsing is normal. The generator handles it , i just hope it's not shortening it's life

Sorry if I wasn't clear, I was talking about at home. It works perfect when home has grid power. On the occasion that we are on genny and powering the home (probably running at 4-6kw, not loafing but not loaded), the Saeco struggles with doing a complete cycle. It often bombs out when packing the puck... I have no idea why.

Maybe the power factor is a bit off from the genny, but everything else in the house works fine, including two AC units if I do some manual load shedding (genny runs on panel, AC and other stuff on other panel).

My only reason to comment on OP was that my "fancy" coffee maker struggles on genny at home which would be similar to the issue of his on the boat.

 

[Pgeee]

Sorry if I wasn't clear, I was talking about at home. It works perfect when home has grid power. On the occasion that we are on genny and powering the home (probably running at 4-6kw, not loafing but not loaded), the Saeco struggles with doing a complete cycle. It often bombs out when packing the puck... I have no idea why.

Maybe the power factor is a bit off from the genny, but everything else in the house works fine, including two AC units if I do some manual load shedding (genny runs on panel, AC and other stuff on other panel).

My only reason to comment on OP was that my "fancy" coffee maker struggles on genny at home which would be similar to the issue of his on the boat.

Ah I see. It’s surprising that coffee makers are an issue vs air con. I’m guessing the pulsing is part of it. Seems this generator and coffee machines subject is a broader discussion. I might do some googling without the word marine

 

[ttmott]

Sorry if I wasn't clear, I was talking about at home. It works perfect when home has grid power. On the occasion that we are on genny and powering the home (probably running at 4-6kw, not loafing but not loaded), the Saeco struggles with doing a complete cycle. It often bombs out when packing the puck... I have no idea why.

Maybe the power factor is a bit off from the genny, but everything else in the house works fine, including two AC units if I do some manual load shedding (genny runs on panel, AC and other stuff on other panel).

My only reason to comment on OP was that my "fancy" coffee maker struggles on genny at home which would be similar to the issue of his on the boat.

Something really doesn't make much sense. The circuit breaker for that outlet is a 15 amp?? If it isn't popping the breaker then the dock and generator power system for the boat isn't the problem. If the coffee maker works at home without issue then something in the circuit's wiring from the boat's breaker to the receptacle.
Did you try another outlet from a different circuit breaker?

 

[Ericinmich]

Something really doesn't make much sense. The circuit breaker for that outlet is a 15 amp?? If it isn't popping the breaker then the dock and generator power system for the boat isn't the problem. If the coffee maker works at home without issue then something in the circuit's wiring from the boat's breaker to the receptacle.
Did you try another outlet from a different circuit breaker?

I tried to be clear in my previous post, I'll try again.

The Saeco machine I'm talking about is only being used at home.
At home it's plugged into a 15a outlet.
It works fine when home hasn't lost power.
When running under genny it often fails on it's cycle. It makes odd sounds, pulsing, and the packing of the puck by the motor will stop, and it quits the cycle.
In this situation, the braker doesn't pop.
In this situation, the gennerator isn't being overloaded, nor can you hear it struggling.
In this situation it doesn't matter if the genny is running lightly loaded or heavily loaded.
Everything else in the house runs fine, it's a 15kw genny and runs perfectly.
I check the voltage, and it's where it should be, maybe moving back and forth a few volts but doesn't do anything different during the situation where Saeco fails.

My undergrad and masters are in EE, so I'm hoping to be smart enough to think through what's going on. I welcome input for suggestions!

My main theory is that the motor in the Saeco does a current or voltage monitor to look at when to stop squeezing the coffee puck. Either the power factor is off enough, or the larger ripple in the voltage/current from the genny trips the logic to stop thinking the motor is stalled, so it backs off.

I will say that 1 of the 3 garage door openers had a similar issue, stopping on the way up or down while on genny. I dailed back the "force detection" a bit and it works fine. I think they use the same logic, monitoring motor current and if too high stop (or back up).

All this typing gets me thinking, maybe I will try to measure the power factor... but everything else in house including ACs, fridges, etc work fine.

 

[techmitch]

Not an EE buy a long stretch but could this be a frequency issue?

 

[Ericinmich]

Not an EE buy a long stretch but could this be a frequency issue?

Frequency does move a bit more on genny, but not much. They way the gennys close loop on the voltage is by monitoring frequency, and when load is added (or removed) the current demand starts to slow down the motor/genny so the frequency drops just a bit, then it opens the throttle. This is how all small generators work, including ones in boats. It faster for a circuit (or ECU) to monitor a small drop in freq an add air faster.

I just know that motors with current sense can have problems.

I do have a 'kill a watt' device around, maybe I will use it to see if anything pops out.