Inrush current limiters

[m_c]

Does anybody know of any mains voltage inrush current limiters, that would limit current to around 2-3 amps?

The full situation.
I work at various events, and can run of a portable power bank for most of the day, however my laser printer (bought to replace the inkjet, as due to the very limited use, the inkjet cost me far more in cartridges, plus there was the continual faff of when it didn't print well when needed!) trips the overcurrent protection on the power bank.

The power bank is a Bluettie AC180, which is capable of 1800W AC (it does have a 2700W power lifting mode, but that changes the output from pure sine wave to a modified wave for resistive loads), and is typically supplying 2-400W through events. The issue is when I go to print, when the laser printer kicks in, it often trips the power bank output.
Officially the printer uses about 400W while actively printing, but having done a bit research about similarly sized laser printers, some manufacturers list a peak current of around 1000W, so there is obviously a surge as the printer heater kicks in.
What I'd like to try, is an inrush current limiter that would limit the current to 2-3A, to see if that's enough for the printer to kick in without causing any problems.

MeanWell do an inrush current limiter (ICL-16), which would seem like the ideal solution, but only in 16A form.

The other options are I buy a bigger power bank (££££), build a system into my van (£££, but removes portability), or go back to an inkjet (££, but lose the benefits of the laser printer).

 

[Guineafowl]

How about some combination of incandescent bulbs in series with the printer? A bit crude, but not much to lose if it doesn’t work. Those linear ones used in older security lights are about 500W and might do the job.

 

[Kram]

Inrush limiters will not work for sustained loads like a heater.

Best bet is try with the modified wave output, most items are quite happy with that.

 

[m_c]

How about some combination of incandescent bulbs in series with the printer? A bit crude, but not much to lose if it doesn’t work. Those linear ones used in older security lights are about 500W and might do the job.

That might work for trial purposes. I'll have to have a rummage around the workshop

 

[m_c]

Inrush limiters will not work for sustained loads like a heater.

I'm guessing the heater element will be PWM controlled to maintain the correct temperature, as provided the power bank doesn't trip and the printer doesn't go back to sleep, I can keep printing without issue.
So I want to establish whether limiting the current will prevent the power bank from tripping, and if the printer will still wake up without generating any errors.

 

[Guineafowl]

That might work for trial purposes. I'll have to have a rummage around the workshop

Just running the printer through a long extension lead might make the difference.

I was also thinking of a series fluo light ballast, but that might cause problems with ringing/oscillation.

 

[voipio]

The laser printer's power surge at the start of printing will last for several seconds. The solution might be to get a higher rated power source (e.g. leisure battery and 3kW inverter perhaps).

Having said that, I've just checked the power consumption of a Laserjet 5L, and it draws a peak power of just under 400W during printing. It might be worth measuring your printer's power consumption, then contacting Bluetti with the measurements obtained.

Does the Bluetti produce any error codes?

 

[bump]

Laser printers will happily draw 8 amps on startup (we used to have to tag the kettle leads to be used with those on site) as it's heating the fuser unit, you're going to really struggle with limiting this down. They are a bit like an oven, takes a fair whack of power to get them up to temp, but much lest to hold them there.

 

[knighty]

what else do you have plugged in?

printer will be fine with modified wave - most electronics will be, they're converting it down to low voltage DC and running from that anyway so it makes no difference to them if it's sine wave or square wave coming in

 

[m_c]

Specs say surge power of 2700W (if I read it properly). That would, perhaps, indicate a faulty unit?

It's what they call "power lifting" mode, which from what i gather, is more a square wave output to saturate resistive loads and provide more power for the same max current.
It's not recommended for sensitive loads.

 

[m_c]

The laser printer's power surge at the start of printing will last for several seconds. The solution might be to get a higher rated power source (e.g. leisure battery and 3kW inverter perhaps).

Having said that, I've just checked the power consumption of a Laserjet 5L, and it draws a peak power of just under 400W during printing. It might be worth measuring your printer's power consumption, then contacting Bluetti with the measurements obtained.

Does the Bluetti produce any error codes?

It seems to be just the initial surge, as when the printer wakes up, you'll hear a relay in it click, and it'll either work, or it'll trip the power bank due to an over load being detected.
When it works, there's only a few hundred watt increase in the power bank load, so I'm guessing there is some kind of inrush current as it powers up.

 

[Kram]

I'm guessing the heater element will be PWM controlled to maintain the correct temperature, as provided the power bank doesn't trip and the printer doesn't go back to sleep, I can keep printing without issue.
So I want to establish whether limiting the current will prevent the power bank from tripping, and if the printer will still wake up without generating any errors.

My guess it will be a PTC heater unit that effectively switches off at the correct temperature. In this case, a traditional inrush varistor may work as PTC's can have very low resistance when cold. However it would need to be directly before the heater and not connected inline with the whole device (which would heat it up and lower its resistance before the heater fires up

Test this, do a print on mains then swap to the powerbank and immediatly try another print. I would guess the heater would already be hot, resistance already higher, so the inrush low.

 

[hotponyshoes]

Does the printer trip the powerbank if it is the only thing plugged into the powerbank?

 

[m_c]

My guess it will be a PTC heater unit that effectively switches off at the correct temperature. In this case, a traditional inrush varistor may work as PTC's can have very low resistance when cold. However it would need to be directly before the heater and not connected inline with the whole device (which would heat it up and lower its resistance before the heater fires up

Test this, do a print on mains then swap to the powerbank and immediatly try another print. I would guess the heater would already be hot, resistance already higher, so the inrush low.

That is what I'm guessing is the issue, and why I'd like to try limiting the current to see if the printer would still function normally, but I've not found anything that could limit the current yet.

 

[Kram]

Inrush limiters are generally, very cheap components, NTC varistors I believe. Datasheet for one, may be useful.

https://product.tdk.com/system/files/dam/doc/product/protection/current/ntc-limiter/data_sheet/50/db/icl_16/s238.pdf

https://www.mouser.co.uk/c/circuit-protection/thermistors/inrush-current-limiters/

 

[Gareth J]

It seems to be just the initial surge, as when the printer wakes up, you'll hear a relay in it click, and it'll either work, or it'll trip the power bank due to an over load being detected.
When it works, there's only a few hundred watt increase in the power bank load, so I'm guessing there is some kind of inrush current as it powers up.

In which case, I'm guessing, it's unlikely to be just a heater that's solely the cause. Because you'd imagine a heater would have a fairly heavy current for more than the initial wake up.

There is probably a bunch of stuff that gets powered up in the printer on startup and things in there like transformers or some capacitors have a relatively huge startup current compared to a relatively tiny running current.

It might be worth opening the printer to see if you can pull something large and basic out of circuit to a separate switch, maybe the heater.... So you can energise the circuitry and then engage the heater via your separate switch. Though this might make the printer unhappy if it's got sensors and error codes etc.

 

[Jack Ryan]

Do you have a clamp meter that will measure inrush current?

There are a few loads that affect startup - like the fuser heater - but it might be just the power supply capacitors charging that is causing the CB to trip. If there is a very short duration high peak, that is likely capacitors charging and an inrush limiter should stop that. If it is a sustained (longer duration) load, it is probably too much for an inrush limiter and may impede the operation of the printer.

I think it is worth trying the "Power Lifting Mode" as long as your other loads don't have a low power factor.

The other thing is - do you really need a printer? If the inkjet is dry when it is needed it would suggest that it is not used often.

Jack

 

[Misterg]

I've not found anything that could limit the current yet

Seriously: Try a high wattage incandescent bulb in series with the supply as suggested above. (With a switch to bypass it if necessary.)

 

[dobbslc]

What's actually tripping?
Is it a MCB or RCBO?

 

[bump]

What's actually tripping?
Is it a MCB or RCBO?

Or software