# Monex card reader VAC too high

#### glk

Joined Aug 26, 2023
3
I am installing 27 Monex credit card readers that are capable of doing 17 different forms of payment as of today and growing. They swipe, stab and do touch and go of virtually every card or wallet out there and consolidate the billing to just one account. The older generation of the competition required 3 different components to do what this guy does in a devise about the size of 2 playing card deck like Hoyle produces. Much of the install has gone well in the wash bays but on the commercial stainless steel vacuum cleaners the units boot get almost ready to go operational then click and start to reboot..the issue is the power . Needs to be 24VAC but nearly all 13 produce 28.3 to 29.5 VAC. I tried a doorbell transformer that is supposed to create 24 VAC but it too creates a little over 28 Of course what they're expecting is that you're going to run along distance of wire and that that thin wire over 50 ft you're going to have a drop and then it will likely be in the range that would work but these are not going more than a foot or two Do I buy 20 to 40 ft of wire and let nature take its course are do they make a buck down voltage regulator for VAC to vac like they do for DC to DC. I took a year of electronic in high school so I only know enough to be dangerous and the price tag on these units leaves me wanting to do it right.Advice?

#### Hymie

Joined Mar 30, 2018
1,284
For a cheaper solution, use a resistor rather than 40ft of wire.

If the current drawn is reasonably stable, you can calculate the required resistance value.

In your application you want to reduce the ac voltage by around 5V, if the current drawn is 50mA, then the required resistor value becomes 5/0.05 = 100Ω with a power rating of at least ¼ watt.

#### Hymie

Joined Mar 30, 2018
1,284
I’d be interested to know if the suggested plug-in dimmer, solves the issue.

If the credit card readers are located in close proximity, the dimmer could probably power more than 10.

#### glk

Joined Aug 26, 2023
3
I am installing 27 Monex credit card readers that are capable of doing 17 different forms of payment as of today and growing. They swipe, stab and do touch and go of virtually every card or wallet out there and consolidate the billing to just one account. The older generation of the competition required 3 different components to do what this guy does in a devise about the size of 2 playing card deck like Hoyle produces. Much of the install has gone well in the wash bays but on the commercial stainless steel vacuum cleaners the units boot get almost ready to go operational then click and start to reboot..the issue is the power . Needs to be 24VAC but nearly all 13 produce 28.3 to 29.5 VAC. I tried a doorbell transformer that is supposed to create 24 VAC but it too creates a little over 28 Of course what they're expecting is that you're going to run along distance of wire and that that thin wire over 50 ft you're going to have a drop and then it will likely be in the range that would work but these are not going more than a foot or two Do I buy 20 to 40 ft of wire and let nature take its course are do they make a buck down voltage regulator for VAC to vac like they do for DC to DC. I took a year of electronic in high school so I only know enough to be dangerous and the price tag on these units leaves me wanting to do it right.Advice?

#### MisterBill2

Joined Jan 23, 2018
18,928
It seems that using an adequate transformer with a suitable current capacity has not been mentioned.
The cheap junk transformers use wire that is not adequate to deliver the needed voltage without an excessive voltage drop. So getting a higher voltage to compensate for the internal voltage drop is burning all that wasted power creating heat,Many of the junk transformers also have an internal over-temperature cutout switch. So if it is acceptable for the card reader to only be usable 70% of the time that will be OK.
OTHERWISE, buy an adequately rated transformer from an electronics supplier and never need to replace it.

glk

#### glk

Joined Aug 26, 2023
3
It seems that using an adequate transformer with a suitable current capacity has not been mentioned.
The cheap junk transformers use wire that is not adequate to deliver the needed voltage without an excessive voltage drop. So getting a higher voltage to compensate for the internal voltage drop is burning all that wasted power creating heat,Many of the junk transformers also have an internal over-temperature cutout switch. So if it is acceptable for the card reader to only be usable 70% of the time that will be OK.
OTHERWISE, buy an adequately rated transformer from an electronics supplier and never need to replace it.