How to slow Spindle ramp on T1 Controller??

Hi Guys,

Im working on an old QT10 with T1 control and Im trying to slow spindle ramp time. Machine is running on a phase converter and im getting an alarm when starting and stopping spindle at high rpms in high gear. Is there a parameter to set this? I cant seem to find anything.

The drive itself (Mitsubishi FR-SB) appears to be not adjustable in terms of acceleration. Specifications say : Accel-Decel Method - Slip-limitation Accel-Decel

I found out that parameter T1 and T2 set the "estimated time for spindle to reach speed." I tried adjusting these with no help. If you have to tell the controller how long it should take to accelerate, does this mean the controller has no control over ramp time? Thanks

Those parameters are just how long the machine sits around with its thumb up its ass waiting for
the spindle to come up to speed...

The actual ramp time is set with dip switches. Its been years since I've done it.. Little
block of 8 tiny dip switches, either on or near the spindle drive... I seem to recall it
was a red plastic block, with white switches.

I don't remember in which manual it tells you what combo on the switches gives you what time..

If nobody gives a better answer by Monday morning, I'll look it up when I get back to the shop.
And I can even take a pic for you if you haven't found it.

Bobw said:

Those parameters are just how long the machine sits around with its thumb up its ass waiting for
the spindle to come up to speed...

The actual ramp time is set with dip switches. Its been years since I've done it.. Little
block of 8 tiny dip switches, either on or near the spindle drive... I seem to recall it
was a red plastic block, with white switches.

I don't remember in which manual it tells you what combo on the switches gives you what time..

If nobody gives a better answer by Monday morning, I'll look it up when I get back to the shop.
And I can even take a pic for you if you haven't found it.

Click to expand...

Yes please post details tomorrow. The FR-SX spindle drive has adjustable acceleration set with dip switches, my older FR-SB does not. Hoping theres something in the controller that will allow me to adjust ramp.

Which drive do you have? I just reduced the acceleration on my FR-SE drive the other day and have the docs for it.

From your previous thread, I'm pretty sure you have a different drive with the T1 controller.



On the FR-SE, you just remove the cover plate from the drive to expose the top-board. There is column of 7 dip switch blocks.
Counting down from the top, the 5th switch block is the one you're interested in. The 3rd, 4th & 5th switches in block 5 control accel/decel time.

The slowest setting is to flip those three switches (bits) off (down). It makes a substantial change in the current drawn by the machine during speed changes. I ran a part with a lot of quick accel/decel steps with an ammeter on the input wiring to the FR-SE drive.

My drive is a FR-SB which i think is one of the oldest Mitsubishi AC drives. There are no dip switches on my drive under the cover. And the manual says accleration is limited based on motor slip, doesn't mention any option of acceleration based on time. Starting to think i might have to live with running in low gear, and the harsh ramps.

I adjusted the slip compensation pot as per manual and its slightly smoother, was off a little. But still ramping very fast, and harsh especially when stopping, even in low range. Pretty sure it will still overload in high range. Wish there was a way to slow it down.

mmurray70 said:

My drive is a FR-SB which i think is one of the oldest Mitsubishi AC drives. There are no dip switches on my drive under the cover. And the manual says accleration is limited based on motor slip, doesn't mention any option of acceleration based on time. Starting to think i might have to live with running in low gear, and the harsh ramps.

I adjusted the slip compensation pot as per manual and its slightly smoother, was off a little. But still ramping very fast, and harsh especially when stopping, even in low range. Pretty sure it will still overload in high range. Wish there was a way to slow it down.

Click to expand...

Might be a good enough reason to upgrade that drive in the future after all. Do you have a PDF of the maintenance manual? I wonder if a guy could hack the old drive to reduce accel/decel?

cwtoyota said:

Might be a good enough reason to upgrade that drive in the future after all. Do you have a PDF of the maintenance manual? I wonder if a guy could hack the old drive to reduce accel/decel?

Click to expand...

Yes i have the maintenance manual and also the wiring schematics. See links below. Let me know if you think it might be possible to mod it. I might be willing to give it a shot.

Maintenance manual: FR-SB Maintenance Manual.PDF - Google Drive

Wiring schematics: FR-SB Schematics.pdf - Google Drive

Hi guys, Just a follow up in case anybody else is ever wondering how to adjust this. I finally figured out how to adjust ramp time on the FR-SB drive. Its done with a pot labeled VR708 and you turn clockwise to increase acceleration time.

Very nice and smooth now and much easier on my small electrical service too. What a difference! Big thanks to SAF in the VFD forum for finding the info hidden in the troubleshooting section of the manual.

mmurray70 said:

Hi guys, Just a follow up in case anybody else is ever wondering how to adjust this. I finally figured out how to adjust ramp time on the FR-SB drive. Its done with a pot labeled VR708 and you turn clockwise to increase acceleration time.

Very nice and smooth now and much easier on my small electrical service too. What a difference! Big thanks to SAF in the VFD forum for finding the info hidden in the troubleshooting section of the manual.

Click to expand...

Glad to hear you found a solution.