The VEM electromagnetic drive has no rotating parts or bearings, so it fails less often than mechanical alternatives, but load on the coil and armature still produces a typical set of faults — most of which can be diagnosed without removing the drive.
Loss of oscillation amplitude
If feeder capacity has noticeably dropped at the same control unit settings, first check the gap between the armature and the electromagnet core (it widens as the rubber elastic elements wear) and that the drive is securely mounted to the tray — a loose mounting absorbs part of the vibration energy.
Coil overheating or breakdown
Overheating is usually caused by running above the rated voltage or by continuous operation in a duty cycle the drive isn't rated for. Coil insulation breakdown is irreversible and requires replacing the coil or the whole drive — prevented by using a control cabinet or unit with current and temperature protection, which is part of the standard wiring scheme.
Armature sticking or knocking against the core
A metallic knocking sound during operation usually indicates wear of the rubber elastic element that limits armature travel, or an amplitude setting issue at the control unit. Running with the armature knocking against the core quickly damages both the coil and the elastic elements — stop the drive for diagnosis as soon as knocking appears.
Control unit protection tripping repeatedly
If the control unit regularly cuts the feeder on protection, that's not a default fault of the unit but a signal that the drive is drawing above-normal current (see above) or that a material blockage is creating constant overload. See the full lineup of ШУВ cabinets and БУВ units and their differences on the control devices page.
Broken or lost contact in the vibration sensor circuit
In automatic mode, tray amplitude is monitored by a vibration sensor mounted on the tray itself. A broken sensor wire or a corroded connector contact is usually read by the control unit as "no signal", and it shuts the feeder off under its own protection logic — from the outside this looks like an unexplained stop with a perfectly healthy drive. Start diagnosis by checking the sensor wiring and connector, not the drive itself.
Incomplete discharge from a hopper
If a noticeable layer of material stays on the tray after the feeder stops, that isn't always a drive fault: it can be material sticking to the tray (moisture, buildup) or insufficient amplitude for that particular bulk material. Rule these out before diagnosing the drive, or you risk removing a perfectly working drive for nothing.
Symptom → likely cause
| Symptom | Likely cause | What to check |
|---|---|---|
| Capacity dropped | Worn elastic elements, loose mounting | Armature-core gap, fasteners |
| Drive runs hot | Overvoltage, no rest in duty cycle | Control unit settings |
| Metallic knocking | Worn elastic element, amplitude off | Armature travel, amplitude setting |
| Protection trips | Overcurrent | Material blockage, current draw |
Preventive maintenance
A scheduled visual check of the mounting and elastic elements, monitoring current draw under normal load, and timely replacement of wear parts all reduce the chance of unplanned downtime. If you're unsure of the diagnosis, send us the drive model and a description of the symptoms via the request form — we'll help remotely or size a replacement drive.