I wanted to test one of the Lego motors without setting up the whole kit. The motor is designed for 4V DC. Dug through my bin of random wall warts. Closest I could find is 5V DC (and 0.5A but I'm not sure if that matters). Snipped off the wart's barrel connector, spliced a mini-banana lead to each wire, and the motor happily spun away. When I tested the Lego computer interface port voltage it showed around 3.7x on my multimeter whereas the wart produces 5 true. Will I cause any long-term damage to the 30-year-old Lego motor by running it at 25% higher voltage than intended?
I wanted to test one of the Lego motors without setting up the whole kit.
The motor is designed for 4V DC.
Dug through my bin of random wall warts. Closest I could find is 5V DC
(and 0.5A but I'm not sure if that matters).
Snipped off the wart's barrel connector, spliced a mini-banana lead to
each wire, and the motor happily spun away.
When I tested the Lego computer interface port voltage it showed around
3.7x on my multimeter whereas the wart produces 5 true.
Will I cause any long-term damage to the 30-year-old Lego motor by
running it at 25% higher voltage than intended? Is there anything printed on the motor to indicate intended input voltage? The components between where the supply connects to the box and the output port to the robot regulate the voltage down before it gets to the motor based on your readings. So, any burning out of components will occur in the "box " not the motor. Short term probably not enough to be a problem. 4v is less likely to be in a parts bin but I am sure a correctly-rated power supply is easy enough to find, I'd get one if you can because a too - hot supply will eventually burn out whatever is regulating the juice down before it gets to the motor. Bil
On Wed, May 10, 2017 at 1:44 AM, Evan Koblentz via vcf-midatlantic < vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
I wanted to test one of the Lego motors without setting up the whole kit. The motor is designed for 4V DC. Dug through my bin of random wall warts. Closest I could find is 5V DC (and 0.5A but I'm not sure if that matters). Snipped off the wart's barrel connector, spliced a mini-banana lead to each wire, and the motor happily spun away. When I tested the Lego computer interface port voltage it showed around 3.7x on my multimeter whereas the wart produces 5 true. Will I cause any long-term damage to the 30-year-old Lego motor by running it at 25% higher voltage than intended?
The 80s Lego motors were marked at 4.5v, whenever you see them for sale. Many of the wall-warts have very weak regulation, if it's the modern variety, and none if much older. I don't recall the current rating on the motor, but you like to find a power supply with enough current, your 0.5A might be just enough Then the windings in the armature of the motor will begin increase their heat dissipation, not good if running for long periods. Once it does get hot, the windings can deform and possibly short together as the enamel insulation beings to melt. If you constantly run the motor at the higher voltage, it's not that much but still, I think it would take a long time to get hot at just 5v, but longer age is a factor, making it further weak The simplest test is the sniff test, if you smell anything emanating from the motor, and not ozone from the commutation contacts, but rather chemical smell, it might be too late. You're safe by with just 2x C or D cell batteries, a battery holder, or recycle an old-school flashlight into a power supply Dam
Basically no, it's almost certainly a mechanically commutated motor, more voltage means it'll spin faster, and spinning faster means it draws less current. Same reason it's OK to run 12V through old 6V automotive starter motors (most of the time). Like Dan said, as long as you don't go way over the nominal voltage, and you're not leaving it hooked up for a while, it's probably fine. Thanks, Jonathan On Wed, 10 May 2017 01:44:04 -0400 Evan Koblentz via vcf-midatlantic <vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
I wanted to test one of the Lego motors without setting up the whole kit.
The motor is designed for 4V DC.
Dug through my bin of random wall warts. Closest I could find is 5V DC (and 0.5A but I'm not sure if that matters).
Snipped off the wart's barrel connector, spliced a mini-banana lead to each wire, and the motor happily spun away.
When I tested the Lego computer interface port voltage it showed around 3.7x on my multimeter whereas the wart produces 5 true.
Will I cause any long-term damage to the 30-year-old Lego motor by running it at 25% higher voltage than intended?
participants (4)
-
Dan Roganti -
Evan Koblentz -
Systems Glitch -
william degnan