Larsen & Toubro · DC Drives
Larsen & Toubro MIDIPACK-4 repair
Get the Larsen & Toubro MIDIPACK-4 repaired rather than replaced. It is matched to an engineer who works on Larsen & Toubro DC drives, and the cost is confirmed before work starts.
Cost confirmed before any work starts · Warranty of 30 days to 6 months
At a glance
The Larsen & Toubro MIDIPACK-4
- Manufacturer
- Larsen & Toubro
- Model / part number
- MIDIPACK-4
- Also searched as
- MIDIPACK4 · MIDIPACK 4
- Description
- DC drive
- Category
- DC Drives
- Service
- Diagnosis and component-level repair, onsite or ship-in
- Warranty
- 30 days to 6 months, confirmed before work starts
Larsen & Toubro equipment in this catalog is listed by model or part number. Send the model from the nameplate and the fault, and it will be matched to an engineer who works on that kind of unit.
Common faults
What usually fails on a unit like the MIDIPACK-4
Thyristor DC drives still run mills, extruders, winders and cranes across Indian plants. Their faults are well understood and almost always repairable: thyristors, firing circuits, field supplies and feedback.
Thyristor and fuse failures
Failed thyristors or semiconductor fuses after a commutation failure, a flashover at the motor or a supply disturbance.
Firing and synchronisation faults
Faults in the pulse transformers or firing board cause uneven current, humming and speed instability.
Field supply faults
Field loss trips, or a motor that overspeeds, point to the field controller or field winding.
Speed feedback problems
A worn tachogenerator, a loose coupling or a failed encoder interface gives speed hunting or overspeed trips.
Armature overcurrent
A mechanical jam, a failing motor commutator or a current-loop fault in the drive.
First checks
What to check before calling an engineer
Isolate and lock out the supply, and wait for stored energy to discharge, before opening anything.
Safe for plant staff
- Record the fault code and whether it trips at start, at speed or on stopping.
- Inspect the motor's brushes and commutator.
- Check the tachogenerator coupling for slip or wear.
Leave to a specialist
- Testing thyristors and firing circuits.
- Adjusting current and speed loops.
- Any work on the armature or field circuits with the supply connected.
Getting it fixed
How to get the MIDIPACK-4 repaired
What to send with it
- The drive, or the power and control sections if it is cabinet-built.
- The fault code and the motor nameplate (armature and field ratings).
- Notes on what the machine does: winder, extruder, mill stand, crane.
Onsite or ship-in
Technicians work onsite from our Hyderabad base and travel to plants across India; anything that can be removed can also be sent to MachineryFix from anywhere in the country.
Warranty. Repairs carry a warranty of 30 days to 6 months, depending on the item and the repair; the exact term is confirmed before work starts.
FAQ
MIDIPACK-4 repair questions
Is the Larsen & Toubro MIDIPACK-4 still repairable when spares are no longer sold?+
Usually. Thyristors, fuses, capacitors and most board components are standard parts, so older DC drives can be repaired long after the maker stops supporting them.
Should the DC motor be checked too?+
Yes, if the drive failed with an overcurrent or flashover. Worn brushes or a damaged commutator will take out a repaired drive again.
Does the Larsen & Toubro MIDIPACK-4 have to be sent in, or can an engineer come to the plant?+
Either. An engineer can diagnose it in place and repair it there or take it away, or the unit can be sent to MachineryFix from anywhere in India. The diagnosis and repair cost are confirmed before any work starts.
Is MachineryFix connected to Larsen & Toubro?+
No. Larsen & Toubro and the model name are used only to identify the equipment. MachineryFix is an independent repair service and is not affiliated with or endorsed by Larsen & Toubro.
Same manufacturer
Other Larsen & Toubro DC Drives
Other manufacturers
DC Drives from other makers
Larsen & Toubro and MIDIPACK-4 are named only to identify the equipment. MachineryFix is not affiliated with or endorsed by Larsen & Toubro.
MIDIPACK-4 down?
Send the fault and what the machine was doing. We'll match an engineer who works on it.