Tetrix Motor Fix

[avanboekel]

After our motor only stalled for about 2 seconds yesterday, we found that it wasn't working. We took apart the motor, and found that the resistor was burnt. We couldn't find anything else on CD about the resistor value and were wondering if anyone else knew what resistor to replace it with. We know it wouldn't be legal for competition, but just for testing purposes, we thought it would be fine.

Thanks for the help!

[Greg Needel]

Originally Posted by avanboekel

After our motor only stalled for about 2 seconds yesterday, we found that it wasn't working. We took apart the motor, and found that the resistor was burnt. We couldn't find anything else on CD about the resistor value and were wondering if anyone else knew what resistor to replace it with. We know it wouldn't be legal for competition, but just for testing purposes, we thought it would be fine.

Thanks for the help!

http://www.chiefdelphi.com/forums/sh...ad.php?t=89848

[dez250]

Please read the whole thread here. You'll get the details you need, including the legal and logical fix.

<Greg beat me to it, same thread.>

[avanboekel]

I've searched that thread, and am not finding the type of resistor that I would need.

[dez250]

The reason you are not finding a resistor value to replace the part with, is because it is not a resistor. Even if it was one, it would not be a logical fix. Because the motor has precisely placed magnets inside, when opened, their alignment is thrown off and thus the motor performance is degraded. My suggestion is to replace the whole motor with a new one and use the thermal protection cable for the power adapter, linked to in the previous thread.

[Malikov16]

In the post it says to replace the resistor. We already ordered new motors which we are saving for competition, but we need motors to work right now so we can work with our minibot.

[dez250]

If you want motors to use to design around and will operate as new motors will in competition, wait for the new motors to arrive in the mail. As mentioned before, the piece you fried, and refer to as a resistor, is in fact not a resistor. Also even if it was, and you replaced that alone, the motor will not operate as it did before you opened it, so any design you make using the failed motor will not act the same when a new motor would be set in it. Wait the few days now for the new motor(s) to arrive, and it will save you the whole regional experience of rebuilding your minibot there.

[Chris is me]

Originally Posted by dez250

Please read the whole thread here. You'll get the details you need, including the legal and logical fix.

<Greg beat me to it, same thread.>

There is no legal fix for their existing motors - only for preventing new motors from burning out.

[WarehouseCrew]

Could anyone using the Tetrix fuse protected motor power cable answer a couple questions:

1. Does it prevent burning up the Tetrix motors (eg. live up to its promise)?
2. Does the fuse act like a circuit breaker (eg. when it cools down it works again) or do you need to replace the fuse/power cable once it has prevented a motor stall ($9 vs. $30 for motor)?
3. If it is a "fuse" that is destroyed while preventing damage to the motor; can just the fuse (hopefully less that $9) be replaced on this cable without violating the FIRST rules?

Thanks.

[Bill_B]

The fuses being mentioned in various places are part of the battery pack. They are mini blade types and reside inside that black bump on one of the wires coming out of the battery pack. If your motor(s) are not running, check the fuses first. Either remove it and check for continuity or just check the wires out of the battery pack for voltage.

A team update has allowed us to use lower amperage fuses. We're currently running one motor on a 4A fuse. I recommend getting a few lower amperage fuses at the very least. I cannot tell you anything about the thermal protector that is available. I also await reports from those who are using them.

[Al Skierkiewicz]

Warehouse,
The $9 Thermal protector is an auto resetting device. The smaller fuse in the battery is not a resettable device and will need to be replaced when/if it burns open. I am sure your mileage will vary on either device. The failures are caused by various designs and the stall characteristics each provides to the motors.