Motor starter recommendations for flywheel press

[sysrq]

Contactor coil on manual star delta starter has burned out due to possible humidity and old age.
The easiest solution was to find a replacement coil, only thing is it's quite ancient so finding a similar size coil is nearly impossible.
Since it's a fairly big flywheel press with a 11 kW motor then sufficient ramp up time is required. Using automated star delta starter with 30 sec. delay would not be enough.
Soft starter is the most economical and effective solution for 11 kW motor compared to star delta starter which costs a bit more (max starting time 10 sec.)
Another thing is in some cases bigger soft starter is needed if the load is too heavy at the start up (then it might not be cost-effective anymore).
Does striving to preserve the manual star delta starter would be the best thing to do?
Manual change over must be carried out depending on the assumptions of machine operator.
Unpredictable transition times between star/delta change over can cause massive current and mechanical spikes.
Thanks a lot.

 

[Bobster]

Fit a VSD, constant torque.

11kW is a baby.

 

[LeeH]

It is, we have a 400kW rocking up shortly for a panel build.

A soft starter would be a cheaper option.

 

[Bobster]

It is, we have a 400kW rocking up shortly for a panel build.

A soft starter would be a cheaper option.

Even that's not massive.

Had to go out to China last year to look at some SCADA work, the site had a 56MW drive.

Price between a decent SS and a VSD for an 11KW motor wont be a great deal different.

It's if he will have to upgrade the safety requirements of the press that's going to be costly. An by modifying the circuit away from a SD starter unless it meets all current legislation he will have to.

 

[sysrq]

Fit a VSD, constant torque.

11kW is a baby.

I have been told the press will get scrapped soon anyway.

VSD is 4 times more expensive than soft start.

 

[Bobster]

I have been told the press will get scrapped soon anyway.

VSD is 4 times more expensive than soft start.

Then why worry about it, change the contactor that has burnt out. Job done.

 

[sysrq]

Then why worry about it, change the contactor that has burnt out. Job done.

Since I can't find the wiring diagram for manual star delta starter I had to reverse engineered it to some point (manual changeover lever auxiliary contacts in series with contactor NO latching contacts).

The contactor is old type with integrated overload protection, the construction is quite unusual so it's hard to figure out the exact wiring.

Another culprit is the casing without din rail. To fit a standard contactor new set of pushbuttons must be fitted and holes drilled.

 

[Bobster]

Since I can't find the wiring diagram for manual star delta starter I had to reverse engineered it to some point (manual changeover lever auxiliary contacts in series with contactor NO latching contacts).

The contactor is old type with integrated overload protection, the construction is quite unusual so it's hard to figure out the exact wiring.

Another culprit is the casing without din rail. To fit a standard contactor new set of pushbuttons must be fitted and holes drilled.

But you'd have to do all that if you were installing a VSD or a SS. Plus it sounds like the safety system will not be up to standard, this will dwarf the cost of the VSD/SS

 

[sysrq]

Thanks for answers. Attached some DIN rail on existing enclosure and used new star delta starter since the star delta starter kit with a 9 Amp overload protection relay was already purchased in a hurry.
According to starter enclosure nameplate it was only a 7.5 kW (10 hp) 15.9 FLA motor (due to plaque couldn't see anything on a motor nameplate), 7.5 kW soft-starter would have been more expensive on average.

Will have to ask for permit to upgrade the safety measures up to current requirements.

 

[joel89]

i have put a soft start schneider/ telemec altistart 22 on a 110kw 3ph motor thats drives a Flywheel forging hammer thats works lovely, I have 30secs for start time but i can set to 2mins if i wanted too, they are so much better no arcing contacts !

 

[sysrq]

i have put a soft start schneider/ telemec altistart 22 on a 110kw 3ph motor thats drives a Flywheel forging hammer thats works lovely, I have 30secs for start time but i can set to 2mins if i wanted too, they are so much better no arcing contacts !

Are they slightly over-sized?
I think 10 secs is enough to reduce initial mechanical stresses.

 

[joel89]

Are they slightly over-sized?
I think 10 secs is enough to reduce initial mechanical stresses.

I went for a 132kw soft start drive just next size up it cost £1100 with wholesaler discount

 

[Bobster]

Dependent on cabling arrangement you could have used a SS inside delta. Would have been able to use one 0.58 the size and saved some £££