I am installing a Variable Frequency Drive (VFD) for the unload system. Is there anything I should know?
The variable frequency drive (VFD) is a good method of protecting the motor and changing speeds of a motor. The VFD changes hertz from 5-72 or anywhere in-between. The more hertz applied the faster the motor runs in RPMs. The downside to the VFD is that it emits noise and signal wiring can pick up noise and vary signals.
- Make sure all signal cables are grounded well on one end.
- Make sure wires for the low voltage and signal are not anywhere close to the VFD.
- The VFD motor output wires should not be close to the 120 VAC control wires.
- Check to see if wire is landed in terminal block properly and not clipped onto insulation instead of wire.
- Check to make sure wire is in properly marked terminal for wire number. Wire number and terminal block number should always match.
When running hard conduit from the high voltage cabinet to the remote cabinet, why do I have to run two separate conduits?
- The signal , Ethernet, communication and thermocouple cables are all vulnerable to noise, induction and signal loss. The best way to protect this wiring from issues is to separate it from any voltage above 24 volt. The 120 volt AC control wiring should run in separate conduit from signal wiring for best results.
- Make certain the cables are all grounded on one end to reduce potential interference.
- The standard remote length is 20′ because it represents the maximum run before the noise, induction and signal loss become a problem.
All moisture control systems that are based off of grain temperature are set up and function the same way. Once the plenum temperature has been established and the dryer is ready to start discharging, the discharge system must be in “manual” mode. Observe the moisture content of the discharging grain. If the grain is too wet, manually slow down the discharge rate. If the grain is too dry, manually increase the discharge rate. Repeat this process until the grain is being discharged at the desired moisture content for several hours. At this point, observe what the mid-grain temperature reading on the HMI is. Enter this number for the mid-grain set point on the HMI. Switch from Manual to TruDry.
It is important to maintain the same plenum temperature as you are going through this process. Remember to allow enough time to see the results of changes made to the discharge system. With all systems, the biggest requirement is patience.
Learn to record what discharge speeds work with different moisture contents, both incoming and discharge and different plenum temperatures. This information can be used in the future to shorted the set up time when establishing the moisture of the discharge.
- The screen that buckles creates a small gap between the screen and the channel ring. This normally develops because the screen material has shifted and hardware is bound end of hole or slot in screen and channel ring. Grain can leak through opening which makes this a functional and appearance issue.
- The proper tool required is a ratchet wrench, nothing battery or electric powered. Loosen the nuts on the ring channel where the buckle or indentation is. Do not remove nut from bolt. Loosen hardware on both sides of buckle. The hardware once loose will allow screen to shift and take normal shape back, hardware can then be re-tightened.
Yes. Use terminals C3 & C4 (which are dry contacts found in the high voltage cabinet) as the command signal for the VFD you are adding. The speed signal for your VFD will be obtained from the dryer’s VFD. Consult your M-C dealer for proper connections.
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