Crown PC 4500:
Voltage to frame

We have around 30 PC4500,s. We are having issues with HID readers going bad. I have found that all lifts have 26 volts going to the frame. Not sure if this is the cause or not, I just don't think it's right. I did discover that the radios we installed had to be isolated from the frame. When doing this my voltage dropped to 14 - 18 volts, witch is acceptable by Crown. But I have some lifts it did not change. Talked to Crown support and they told me to start disconnecting components until I find the issue. I have disconnected about everything and still have issue. Has anyone had this issue? I can understand if this was only one lift with the issue but I have 20+ with this issue. I can say the lifts work fine, no error codes. I'm just trying to explain why we have so many HID readers going bad.
  • Posted 31 Dec 2018 10:07
  • Discussion started by Redman
  • Alabama, United States
Challenge accepted
Showing items 1 - 9 of 9 results.
As far as your InfoLink card readers failing... I think that is an issue Crown has with the card readers themselves. My company just jumped on board with InfoLink about 6 months ago. The dealership came in and installed Infolink on all 70 of our trucks. In the last 6 months I think we have had at least 12 card readers fail. Talking to the local road guys it sounds like they replace quit a few of them.
  • Posted 30 May 2019 02:04
  • Reply by chevotaman
  • Texas, United States
It's all just nuts n' bolts.
your voltage thing with the motors is not specific to crowns design, all motors can do it, especially if they have brushes. Even brushless A/C motors can do it if they get enough dirt in the field windings.

As for your Motorola radios picking up voltage through the mount?
I'd say the radio was intended to be grounded through the mount so you could isolate that by going into the radio and moving the ground from the mount to a separate ground that would connect directly to negative, of just removing it all together, it's probably a secondary ground point. But your solution of isolating the mount plate is probably the simplest solution.
  • Posted 13 Jan 2019 17:15
  • Modified 13 Jan 2019 17:16 by poster
  • Reply by swoop223
  • North Carolina, United States
You've been swooped!
We installed Motorola two way radios on all our lifts. While disconnecting components we found some lifts dropped to 14 volts when the radio was disconnected. Others remained at 26 volts. We had to isolate the radios by installing a insulator between the radio and the Crown accessory clamp.
  • Posted 13 Jan 2019 10:37
  • Reply by Redman
  • Alabama, United States
Challenge accepted
What do you mean by the radios you installed?
  • Posted 13 Jan 2019 09:40
  • Reply by mrfixit
  • New York, United States
Just an update on my voltage to frame issue. After disconnecting component after component I have found a issue with the lift pump. The voltage to frame was 26V,after I disassembled and blew out the motor my voltage dropped to less than 2 volts. I feel this is a design issue with Crown. There is no access to blow out the motor. Let my say again, the lift is working fine. No error codes. We are having issues with INFOLINK card readers going bad. Can anyone tell me if voltage to the frame has an effect on these readers. So far I have disassembled and cleaned the lift pump on four lifts and three dropped to less than 2 volts and one was less than 1 volt.
  • Posted 13 Jan 2019 02:34
  • Modified 13 Jan 2019 02:36 by poster
  • Reply by Redman
  • Alabama, United States
Challenge accepted
I considered rigging up a light bulb and toughting it to the frame. I don't think we have a 26v bulb in the shop. Is there another way to test a short to frame?
  • Posted 1 Jan 2019 00:40
  • Reply by Redman
  • Alabama, United States
Challenge accepted
Have you ran a short to frame test?
  • Posted 1 Jan 2019 00:14
  • Reply by BREWSKI
  • Nebraska, United States
I did that, voltage stayed the same. We have Hydrogen fuel cells. All lifts are less than six months old.
  • Posted 31 Dec 2018 12:18
  • Reply by Redman
  • Alabama, United States
Challenge accepted
try pulling the battery, get a jumper extension harness for the battery, connect it to the truck while the battery is out of the machine and then see what you get.
In most electric's i've worked on, especially older units with older batteries the batteries tend to get acid between the cell's and can cause a bleed effect from the case of the battery to the frame and it back feeds through the motors into the electrical system. If your motors are isolated well from the frame then check the standoff isolators on the power cables, there are some in the main battery cable circuit to the panel, i have seen those go bad on occasion.
Most of the time you may not even notice anything wrong (except if you have accessories attached, they do not have the capability to handle any huge differences caused by this which may be why your having issues).
Once you get the battery removed, if the voltage dissappears theres your answer. If it does not then go by what crown said and start disconnecting components till it goes away.
  • Posted 31 Dec 2018 11:17
  • Modified 31 Dec 2018 11:20 by poster
  • Reply by swoop223
  • North Carolina, United States
You've been swooped!

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