Fw: D1D40 SSR's burning out?? [TANKS]

[Grant Mahalek <gmahalek-at-shaw.ca>]

Hi there,

 

I've run into a bit of a problem in the construction of my Hetzer.  I've burned out three Crydom SSR's with my Anvilus proportional motor controller.  I've sent off an email to www.crydom.com today in hopes of getting some suggestions.  The Crydom website mentions something called "Transient Protection" and protection of the SSR's using fast recovery type diodes with PIV rated greater than supply voltage(....cool....unfortunately I don't completely understand this). Has anyone out there

 

In the "Tri-Pact News Service" article entitled "R/C Combat Vehicles Speed Controls" under the section "Other Issues" various devices are recommended to limit power surges and radio interference.  After a small fix(installation of a CMOS NAND 4011 Gate) into the steering and throttle servo leads, radio interference is no longer a problem.

 

However, burning out these SSR's is becoming a bit of a pain....xxo!!/?##.

 

Can anyone out there offer suggestions, detailed or otherwise on how to overcome this obstacle?  Any suggestions would be much appreciated.

 

Oh, by the way, the rubber boat roller drive wheels did not work, the rubber was too hard and the drive wheels slipped in the tracks.  I'am going to use the "tried and true" TTS rubber bungee cord wrapped plywood drive wheels.  And for those of you wondering about what thickness of drive-shaft to use, I support Steve Tyng's suggestion to use a hardened steel shaft > 1/2 inch.  I've already bent both my 1/2 inch drive shafts in the minimal testing I've done so far.

 

Supper call....thanks for any help you guys can offer.

 

 

Grant P. Mahalek

 

----- Original Message -----

From: Grant Mahalek

To: support-at-crydom.com

Sent: Tuesday, November 01, 2005 7:33 AM

Subject: D1D40 SSR's burning out??

Hello there,

 

 

I'am a hobbyist using a pair of Crydom D1D40 SSR's with a motor controller to provide proportional speed control for a custom built 1:6 scale radio control combat tank. The motor controller(Anvilus RC Relay SSR Motor Controller; Board h_050412, Manual 050425) is described in detail at www.anvilus.com . The motor and control system is wired according to figure 3, page 5 of the manual.  I'am using a pair of new electric scooter motors(MY1016) from www.unitemotor.com operated at 24Vdc. Motor specifications: 24Vdc, 2750 rpm, 15.4amps, 280watts. There is a 40 amp automotive fuse installed in-line on the each motor power lead.  No other circuit protection is provided.

 

I have burned out three(3) Crydom D1D40 SSR's thus far.  This is getting a little expensive for a hobby......

 

Can you help?

 

Circumstances of failures:

 

1.)Test #1; left SSR failed; left SSR -1 terminal wires became loose during tank test run. Up to this time(20 minutes of run time), the electronics and drive system were operating with full mixing and proportional speed control.  Right drive motor and right SSR became very hot.

 

2.)Test #2; right SSR failed after about 20 minutes of fully proportional run-time. No apparent loose electrical connections. No apparent mechanical binding in drive-train. Right drive motor became very hot.

 

Apparently, there are twenty to thirty RC combat tanks using the same electronics(with Crydom SSR's) and drive systems with almost identical components with no problems.

 

Do you have any suggestions regarding the inclusion of circuits or components to protect the SSR's from being burned out.  Could you please be very specific with any suggestions regarding protective circuits or components(ie.-component/circuit installation into motor control wiring and type and specific sizes of and sizes of any components).

 

 

Thank you,

 

 

Grant P. Mahalek

gmahalek-at-shaw.ca

403-948-6443(res)

403-880-2070(bus, cell)