No problem EN.Hi spec! Thanks for your very informative reply.
Got it.Yes "bump car" is a "dodgem car" like the ones at amusement parks. Basically the motor is placed at the front wheels and then the batteries are placed at the back under the car seat.
Sounds good. A direct connection will potentially be more efficient.Actually the dodgem cars initially had a control board which had a timer for cut off and to control sounds and lights. Unfortunately, there were a lot of factors that affected the board's performance and the boards eventually fried. So as a temporary solution what we did was remove the breaker and the board and just used the foot pedal as on/off switch for the motor. Yep the kids were very happy as the cars were really really fast haha
Thanks. Are the wires, connections etc substantial, like a car starter motor wiring (no picture).To give you a simple diagram of the car:
24v batteries --> single pole 63a toggle switch breaker --> control board --> foot pedal switch --> motor
No comment for time being but there are ways to protect against damp.1. Mist/dew issues - this caused our control boards and breaker to get wet at night due to the cold weather at night (19-20 C)
Sorry- I do not understand this. Can you elaborate?2. Welding issues - since the negative pole of the battery is connected to the body, the carbon brush located under the steering wheel neck would make contact with the body and fried the expensive boards
No comment for time being- more details of the board would be required- a schematic would be ideal.1. if we were to buy new boards, how do we electronically protect it from frying if there is a short circuit?
From what you have said, my feeling is to get the simple configuration, without control board, working with a fuse first.2. simple motor protection in case we decide not to buy new boards. thermal cut out and voltage cut out?
Hmm, having a break where the motor can cool is good, but the nature of dodgem cars is continuous stop start, which puts surge currents into the motor.We run the cars at 3 minute intervals and so far the only items getting hot were the fuses and fuse holders. Since they gave out and we kept changing fuses we decided to remove them too
Not sure what you mean? Originally when the boards were working the wires the manufacturer used were gauge #14 or #16. When we bypassed the control board and connected the motor directly to the battery we changed the wires to automotive gauge #12.Thanks. Are the wires, connections etc substantial, like a car starter motor wiring (no picture).
The steering wheel neck is welded to the body. Unfortunately, the manufacturer didn't weld it properly so they gave out. The motor is connected under the steering wheel and since the positive is connected to the carbon brush and the negative is connected to the body, when they meet there is a short circuit.re: welding ... Sorry- I do not understand this. Can you elaborate?
No comment for time being- more details of the board would be required- a schematic would be ideal.
Yup the question though is what kind of fuse to use. I was wondering why they used a 63a toggle switch breaker when the motor is only rated at 14.5a?From what you have said, my feeling is to get the simple configuration, without control board, working with a fuse first.
I don't think we have those kind but will check some electronics stores at the downtown area. ThanksOr do you have access to other high power fuse types like this for example, which would be ideal as it has screw terminals:
Yup on weekends and holidays they continuously run from opening until closing. Yes the accelerator only acts as an on/off switch, it doesn't have any throttle function. So the motor immediately runs fast as soon as you step on the pedal.Hmm, having a break where the motor can cool is good, but the nature of dodgem cars is continuous stop start, which puts surge currents into the motor.
Am I right in thinking that the accelerator is simply an on off switch?
Can you confirm that the motor is not getting excessively hot? The cooler you can make a motor the more reliable the motor will be, so maximum heat convection (ventilation) and conduction is advisable.
Do the motors ever fail (apart from brushes wearing out)?
spec
PS I hope we are going to see some pictures of the dodgem rink in action.
Hmmm ... so maybe that explains why they used a 63a toggle switch breaker? Sometimes those breakers give out too. I've replaced all of them since they kept on tripping. Are there any weatherproof breakers? I saw push button ones online. Are they more durable?If 14.5A is the rated current, at start-up and when stalled (very likely in a dodgem car) the current will be way above that, e.g >70A . No wonder a 30A fuse doesn't survive. Try a 50A one.
I see. #12 standard wire gauge (SWG) or American wire gauge (AWG) is better but not sufficient in my view. But that is from an efficiency point of view and also to minimize the fuse heating.Originally when the boards were working the wires the manufacturer used were gauge #14 or #16. When we bypassed the control board and connected the motor directly to the battery we changed the wires to automotive gauge #12.
Oh OK. That is purely a mechanical problem, even though it has electrical implications.The steering wheel neck is welded to the body. Unfortunately, the manufacturer didn't weld it properly so they gave out. The motor is connected under the steering wheel and since the positive is connected to the carbon brush and the negative is connected to the body, when they meet there is a short circuit.
I see. Do you have a link to the suppliers advert? Specifically, what is the board intended to do?sorry no schematics [for board]- from Chinese supplier
That toggle switch looks like a standard mains consumer unit switch.Yup, the question though is what kind of fuse to use. I was wondering why they used a 63a toggle switch breaker when the motor is only rated at 14.5a?
Thought so- I remember the jolt when setting off on a bumper car. Although all the bumper cars I have seen were overhead powered from a massive diesel electric set.Yes the accelerator only acts as an on/off switch, it doesn't have any throttle function. So the motor immediately runs fast as soon as you step on the pedal.
Can you reach the motor? If so, give one of the motors a good loading and measure the temperature of the motor.I'm not sure if the motor gets too hot ... but I'm assuming it does that's why I'm scared to keep it running this way without any sort of protection
Great pics- thanks.Yup, on weekends and holidays they continuously run from opening until closing. Here are some pictures will send clear ones when I get back at the park
I wondered about that too, but most motors are designed to run balls-out. I would not think that a bumper car weighs much so the power required to accelerate it should not be that high. Also the motor is geared down before driving the wheels.Also, the original controller was likely PWM, so the start-up and running current was likely controlled by a current sensor. Running it balls-out all of the time is likely to smoke the motor...
Not sure about the resistances of the wires. What wire gauge would you recommend? #10? How about for connecting the batteries? We use #8 to series the batteries and I think the ones installed on the car are #10 from the batteries to the breaker.I see. #12 standard wire gauge (SWG) or American wire gauge (AWG) is better but not sufficient in my view. But that is from an efficiency point of view and also to minimize the fuse heating.
Wire rating has two aspects:
(1) Heating effects. So if you see a certain wire has a rating of x amps that means that the wire temperature will not get higher than the safe limit for that wire in free air with x amps flowing in it.
(2) Resistance. Wire is in fact a resistor and, in an application, you need to consider the effect of the total resistance of the wire. For example, if the total wire resistance were 0.1 Ohms and you had 30A flowing in the wire, you would lose 3V of your 24V in the wire. Very often, especially in high current applications, the wire needs to be much heavier than the wire maximum current rating would indicate.
Sorry they don't have the board or any of their parts on their website. The board does the following:I see. Do you have a link to the suppliers advert? Specifically, what is the board intended to do?
Uh huh looks like it. Am trying to look for an alternative weatherproof breaker but the supplies here are limited. Would most likely need to import those parts. Noted on the thicker wires will replace them ASAP.That toggle switch looks like a standard mains consumer unit switch.
You may be able to use a similar sized unit which is an over current trip in place of the thermal fuse you are presently using, say 60A to 80A or you may even need to go to 100A.
In general, the fuse should not be heated by its joining wires and connectors, so thick wires and large contact areas adjoining the fuse are a good move.
Yup we have spare cars on charge and just switch them up whenever they run out of batteries.Thought so- I remember the jolt when setting off on a bumper car. Although all the bumper cars I have seen were overhead powered from a massive diesel electric set.
I expect you need to change batteries quite often during the day. Or do you have spare cars on charge?
The motor is hard to reach when the batteries are installed. We would need to remove the batteries first so the acid inside won't spill when we turn the car to its side. Will try to test this as well. What would be an efficient temperature range for this kind of motor? How hot is too hot?Can you reach the motor? If so, give one of the motors a good loading and measure the temperature of the motor.
You can always protect the motor by simply fitting a high power resistor in series. That will knock the edge off the performance though but not that much and it will give a smoother start.
Nice I hope he makes one soonGreat pics- thanks.
I used to love bumper cars when I was a nipper- in fact I still do. Hopefully I will have an excuse to drive a bumper car again when our son does his duty and provides some grandchildren.
spec
Hi Max how many amperes would you recommend? We'll try to look for those HRC fuses. ThanksNo wonder you are blowing fuses using an automotive style, you need HRC fuse (high rupturing capacity) this way you can fuse lower than would be required from an automotive fuse, these HRC withstand the initial inrush and stop start conditions.
Max.
Hmmm.... mine is more of limiting acceleration/speed to meet the battery capacity hehe ... running the motor at full speed drains it fasterThere is another aspect - safety. I wonder if there is a limit to the acceleration/speed to meet safety requirements.
spec
Each car weighs approximately 150-200 lbs. Re: PWM ... yes I think the board does that too. I forgot to mention it controls the lights too. I'm hoping the motors could run at full speed without burning up but of course I don't want to take chancesI wondered about that too, but most motors are designed to run balls-out. I would not think that a bumper car weighs much so the power required to accelerate it should not be that high. Also the motor is geared down before driving the wheels.
As far as I can remember, the UK bumper cars of old had no control electronics at all- just a foot switch.
spec
I would be inclined to take some empirical tests first, if you can get hold of a clamp-on ammeter.Hi Max how many amperes would you recommend? We'll try to look for those HRC fuses. Thanks
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